0001524741-24-000007 | 10-K | XBRL Viewer

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Debt - Contractual Maturities of Senior Secured Credit Facility (Details) - Senior Secured Credit Facility - Term Loan - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
2024	$ 8,750
2025	8,750
2026	8,750
2027	8,750
2028	8,750
Thereafter	824,313
Total	$ 868,063	$ 1,059,062

Leases - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows for operating leases	$ 25,541	$ 22,410
Financing cash flows for finance leases	1,009	1,576
Right-of-use assets obtained in exchange for new lease liabilities:
Operating leases	4,768	14,744
Finance leases	$ 1,626	$ 2,536

Segment Reporting (Tables)

12 Months Ended

Dec. 31, 2023

Segment Reporting [Abstract]

Schedule of Sales and Segment Contribution Margin for Reporting Segments and Operating Results

The following table presents sales and segment contribution margin (in thousands) for the reportable segments and other operating results not allocated to the reported segments:


	Year Ended December 31,
	2023		2022		2021
Sales:
Oil & Gas Proppants	$	994,276	$	961,667	$	615,448
Industrial & Specialty Products	557,746		563,480		488,431
Total sales	1,552,022		1,525,147		1,103,879
Segment contribution margin:
Oil & Gas Proppants	361,998		301,837		160,052
Industrial & Specialty Products	187,665		170,280		168,499
Total segment contribution margin	549,663		472,117		328,551
Operating activities excluded from segment cost of sales	(18,268)		(17,159)		(19,655)
Selling, general and administrative	(118,797)		(143,838)		(119,628)
Depreciation, depletion and amortization	(137,259)		(140,166)		(161,131)
Goodwill and other asset impairments	—		—		(202)
Interest expense	(101,709)		(77,598)		(71,157)
Other income, net, including interest income	21,939		10,643		6,146
Income tax (expense) benefit	(49,080)		(26,159)		2,755
Net income (loss)	$	146,489	$	77,840	$	(34,321)
Less: Net loss attributable to non-controlling interest	(436)		(336)		(560)
Net income (loss) attributable to U.S. Silica Holdings, Inc.	$	146,925	$	78,176	$	(33,761)

Summary of Significant Accounting Policies	12 Months Ended
Summary of Significant Accounting Policies	Dec. 31, 2023
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	NOTE B—SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation and Consolidation The accompanying Consolidated Financial Statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”). In the opinion of management, all adjustments necessary for a fair presentation of the Consolidated Financial Statements have been included. Such adjustments are of a normal, recurring nature. Throughout this report we refer to (i) our Consolidated Balance Sheets as our “Balance Sheets,” (ii) our Consolidated Statements of Operations as our “Income Statements,” and (iii) our Consolidated Statements of Cash Flows as our “Cash Flows.” Consolidation The Consolidated Financial Statements include the accounts of Holdings and its direct and indirect wholly-owned subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. Use of Estimates and Assumptions The preparation of Consolidated Financial Statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the related disclosure of contingent assets and liabilities at the date of the Consolidated Financial Statements and the reported amounts of revenues and expenses during the reporting period. The areas requiring the use of management estimates and assumptions relate to the purchase price allocation for businesses acquired; mineral reserves that are the basis for future cash flow estimates utilized in impairment calculations and units-of-production amortization calculations; environmental, reclamation and closure obligations; estimates of recoverable minerals; estimates of allowance for credit losses; estimates of fair value for certain reporting units and asset impairments (including impairments of goodwill, intangible assets and other long-lived assets); write-downs of inventory to net realizable value; equity-based compensation expense; post-employment, post-retirement and other employee benefit liabilities; valuation allowances for deferred tax assets; contingent considerations; reserves for contingencies and litigation and the fair value and accounting treatment of financial instruments. We base our estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances. Accordingly, actual results may differ significantly from these estimates under different assumptions or conditions. Cash and Cash Equivalents Cash and cash equivalents consist of all highly liquid investments with a maturity of three months or less when purchased. Because of the short maturity of these investments, the carrying amounts approximate their fair value. Cash and cash equivalents are invested primarily in money market securities held by financial institutions with high credit ratings. Accounts at each institution are insured by the Federal Deposit Insurance Corporation. Cash balances at times may exceed federally-insured limits. We have not experienced any losses in such accounts and believe we are not exposed to any significant credit risk on cash. Accounts Receivable The majority of our accounts receivable are due from companies in the oil and natural gas drilling, building and construction products, filler and extenders, filtration, glass, absorbents, sports and recreation, foundry and other major industries. Credit is extended based on evaluation of a customer’s financial condition and, generally, collateral is not required. Accounts receivable are stated at amounts due from customers net of allowance for credit losses. Accounts outstanding longer than the payment terms are considered past due. We determine our allowance by considering a number of factors, including the length of time trade accounts receivable are past due, our previous loss history, the customer’s current ability to pay its obligation to us and the condition of the general economy and the industry as a whole. Ongoing credit evaluations are performed. We write-off accounts receivable when they are deemed uncollectible, and payments subsequently received on such receivables are credited to the allowance for credit losses. See Note E - Accounts Receivable and Note S - Revenue. Inventories Inventories include raw stockpiles, in-process product and finished product available for shipment, as well as spare parts and supplies for routine facility maintenance. We value inventory at the lower of cost and net realizable value. Cost is determined using the first-in, first-out and average cost methods. Our inventoriable costs include production costs and transportation and additional service costs as applicable. See Note F - Inventories. Property, Plant and Mine Development Plant and equipment Plant and equipment is recorded at cost and depreciated over their estimated useful lives. Interest incurred during construction of facilities is capitalized and depreciated over the life of the asset. Costs for normal repairs and maintenance that do not extend economic life or improve service potential are expensed as incurred. Costs of improvements that extend economic life or improve service potential are capitalized and depreciated over the estimated remaining useful life. Depreciation is recorded using the straight-line method over the assets’ estimated useful lives as follows: buildings (15 years); land improvements (10 years); machinery and equipment, including computer equipment and software (3-10 years); furniture and fixtures (8 years). Leasehold improvements are depreciated over the shorter of the asset life or lease term. Construction-in-progress is primarily comprised of machinery and equipment which have not yet been placed in service. Mining property and development Mining property and development includes mineral deposits and mine exploration and development. Mineral deposits are initially recognized at cost, which approximates the estimated fair value on the date of purchase. Mine exploration and development costs include engineering and mineral studies, drilling and other related costs to delineate an ore body, and the removal of overburden to initially expose an ore body for production. Costs incurred before mineralization are classified as proven and probable reserves are expensed and classified as exploration or advanced projects, research and development expense. Capitalization of mine development project costs, which meet the definition of an asset, begins once mineralization is classified as proven and probable reserves. The cost of removing overburden and waste materials to access the ore body at an open pit mine prior to the production phase are referred to as “pre-stripping costs.” Pre-stripping costs are capitalized during the development of an open pit mine. The production phase of an open pit mine commences when saleable minerals, beyond a de minimis amount, are produced. Stripping costs incurred during the production phase of a mine are variable production costs that are included as a component of inventory to be recognized in costs applicable to sales in the same period as the revenue from the sale of inventory. Depletion and amortization of mineral deposits and mine development costs are recorded as the minerals are extracted, based on units of production and engineering estimates of mineable reserves. The impact of revisions to reserve estimates is recognized on a prospective basis. See Note G - Property, Plant and Mine Development. Mine reclamation costs and asset retirement obligations We recognize the fair value of any liability for conditional asset retirement obligations, if sufficient information exists to reasonably estimate the fair value of the liability. These obligations include environmental remediation liabilities when incurred, which is generally upon acquisition, construction or development and/or through the normal operation of the asset. These obligations also generally include the estimated net future costs of dismantling, restoring and reclaiming operating mines and related mine sites in accordance with federal, state, local regulatory and land lease agreement requirements. The liability is accreted over time through periodic charges to earnings. In addition, the asset retirement cost is capitalized as part of the asset’s carrying value and amortized over the life of the related asset. Reclamation costs are periodically adjusted to reflect changes in the estimated present value resulting from the passage of time and revisions to the estimates of either the timing or amount of the reclamation and abandonment costs. The reclamation obligation is based on when spending for an existing environmental disturbance will occur. If the asset retirement obligation is settled for other than the carrying amount of the liability, a gain or loss is recognized on settlement. We review, on an annual basis, unless otherwise deemed necessary, the reclamation obligation at each mine site in accordance with ASC guidance for accounting for reclamation obligations. See Note K - Asset Retirement Obligations. Impairment or Disposal of Property, Plant and Mine Development We periodically evaluate whether current events or circumstances indicate that the carrying value of our property, plant and equipment assets may not be recoverable. If circumstances indicate that the carrying value may not be recoverable, we estimate future undiscounted net cash flows using estimates of proven and probable sand reserves, estimated future sales prices (considering historical and current prices, price trends and related factors) and operating costs and anticipated capital expenditures. If the undiscounted cash flows are less than the carrying value of the assets, we recognize an impairment loss equal to the amount by which the carrying value exceeds the fair value of the assets. The recoverability of the carrying value of our mineral properties is dependent upon the successful development, start-up and commercial production of our mineral deposit and the related processing facilities. Our evaluation of mineral properties for potential impairment primarily includes assessing the existence or availability of required permits and evaluating changes in our mineral reserves, or the underlying estimates and assumptions, including estimated production costs. Assessing the economic feasibility requires certain estimates including the prices of products to be produced and processing recovery rates, as well as operating and capital costs. Gains on the sale of property, plant and mine development are included in income when the assets are disposed of provided there is more than reasonable certainty of the collectability of the sales price and any future activities required to be performed by us relating to the disposal of the assets are complete or insignificant. Upon retirement or disposal of assets, all costs and related accumulated depreciation or amortization are written-off. Goodwill and Other Intangible Assets and Related Impairment Our intangible assets consist of goodwill, which is not amortized, indefinite-lived intangibles, which consist of certain trade names that are not subject to amortization, intellectual property and customer relationships. Intellectual property mainly consists of patents and technology, and it is amortized on a straight-line basis over an average useful life of 15 years. Customer relationships are amortized on a straight-line basis over their useful life of 13 - 20 years. Intangible assets that are amortized are reviewed for impairment annually, or more frequently when indicators of impairment exist. Goodwill represents the excess of the purchase price of business combinations over the fair value of net assets acquired. Goodwill and trade names are reviewed for impairment annually as of October 31, or more frequently when indicators of impairment exist. An impairment exists if the fair value of a reporting unit to which goodwill has been allocated, or the fair value of indefinite-lived intangible assets, is less than their respective carrying values. Prior to conducting a formal impairment test, we have an option to assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that is more likely than not (more than 50%) that the fair value of a reporting unit is less than its carrying amount. Such qualitative factors may include the following: macroeconomic conditions; industry and market considerations; cost factors; overall financial performance; and other relevant entity-specific events. If the qualitative assessment determines that an impairment is more likely than not, or if we choose to bypass the qualitative assessment, we perform a quantitative assessment by comparing the fair value of a reporting unit with its carrying amount and recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. A trade name is a legally protected trade or similar mark. Acquired trade names are valued using an income method approach, generally the relief-from-royalty valuation method. The method uses a royalty rate based on comparable marketplace royalty agreements for similar types of trade names and applies it to the after-tax discounted free cash flow attributed to the trade name. The discount rate used is based on an estimated weighted average cost of capital and the anticipated risk for intangible assets. The valued trade names have an indefinite life based on our plans and expectations for the trade names going forward and are reviewed for impairment annually, or more frequently when indicators of impairment exist. Intellectual property and technology (“IP”) is a design, work or invention that is the result of creativity to which one has ownership rights that may be protected through a patent, copyright, trademark or service mark. IP is valued using the relief-from-royalty valuation method. The method uses a royalty rate based on comparable marketplace royalty agreements for similar types of IP and applies it to the after-tax discounted free cash flow attributed to the IP. The discount rate used is based on an estimated weighted average cost of capital and the anticipated risk for intangible assets. The IP is amortized following the pattern in which the expected benefits will be consumed or otherwise used up over each component’s useful life, based on our plans and expectations for the IP going forward, which is generally the underlying IP’s legal expiration dates. IP is reviewed for impairment annually, or more frequently when indicators of impairment exist. Customer relationships are intangible assets that consist of historical and factual information about customers and contacts collected from repeat transactions with customers, with or without any underlying contracts. The information is generally organized as customer lists or customer databases. We have the expectation of repeat patronage from these customers based on the customers’ historical purchase activity, which creates the intrinsic value over a finite period of time and translates into the expectation of future revenue, income, and cash flow. Customer relationships are valued using projected operating income, adjusted for estimated future existing customer growth less estimated future customer attrition, net of charges for net tangible assets, IP charge, trade name charge and work force. The concluded value is the after-tax discounted free cash flow. Customer relationships are reviewed for impairment annually, or more frequently when indicators of impairment exist. See Note H - Goodwill and Intangible Assets. Leases We lease railroad cars, office space, mining property, mining/processing equipment, and transportation and other equipment. Operating leases are included in lease right-of-use (“ROU”) assets, current portion of operating lease liabilities, and operating lease liabilities in our consolidated balance sheets. Finance leases are included in lease right-of-use assets, current portion of long-term debt, and long-term debt in our consolidated balance sheets. Leases with an initial term of 12 months or less are not recorded on the balance sheet. ROU assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. ROU assets and liabilities are recognized at the commencement date of the lease based on the present value of lease payments over the lease term. As most of our leases do not provide an implicit rate, we use our incremental borrowing rate based on the information available at the commencement date in determining the present value of lease payments. The ROU assets also include any lease payments made at or before the commencement date of the lease and excludes lease incentives. Our lease terms may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Lease expense for lease payments is recognized on a straight-line basis over the lease term. We have lease agreements with lease and non-lease components, the latter of which are generally accounted for separately. See Note Q - Leases. We periodically evaluate whether current events or circumstances indicate that the carrying value of our ROU assets exceeds fair value. If circumstances indicate an impairment exists, we estimate fair value primarily utilizing internally developed cash flow models and quoted market prices, discounted at an appropriate weighted average cost of capital. If the undiscounted cash flows are less than the carrying value of the assets, we recognize an impairment loss equal to the amount by which the carrying value exceeds the fair value of the assets. Revenue Recognition Products We derive our product sales by mining and processing minerals that our customers purchase for various uses. Our product sales are primarily a function of the price per ton and the number of tons sold. We primarily sell our products through individual purchase orders executed under short-term price agreements or at prevailing market rates. The amount invoiced reflects product, transportation and additional handling services as applicable, such as storage, transloading the product from railcars to trucks and last mile logistics to the customer site. We invoice most of our product customers on a per shipment basis, although for some larger customers, we consolidate invoices weekly or monthly. Standard collection terms are net 30 days, although extended terms are offered in competitive situations. We recognize revenue for products and materials at a point in time following the transfer of control of such items to the customer, which typically occurs upon shipment or delivery depending on the terms of the underlying contracts. We account for shipping and handling activities related to product and material sales contracts with customers as costs to fulfill our promise to transfer the associated products pursuant to the accounting policy election allowed under ASC 606-10-25-18b. Accordingly, we record amounts billed for shipping and handling costs as a component of net sales and accrue and classify related costs as a component of cost of sales at the time revenue is recognized. For a limited number of customers, we sell under long-term, minimum purchase supply agreements. These agreements define, among other commitments, the volume of product that our customers must purchase, the volume of product that we must provide and the price that we will charge and that our customers will pay for each product. Prices under these agreements are generally fixed and subject to certain contractual adjustments. Sometimes these agreements may undergo negotiations regarding pricing and volume requirements, which may often occur in volatile market conditions. While these negotiations continue, we may deliver product at prices or at volumes below the requirements in our existing supply agreements. An executed order specifying the type and quantity of product to be delivered, in combination with the noted agreements, comprise our contracts in these arrangements. Service We derive our service revenues primarily through the provision of transportation, equipment rental, and contract labor services to companies in the oil and gas industry. Transportation services typically consist of transporting customer proppant from storage facilities to proximal well-sites and are contracted through work orders executed under established pricing agreements. The amount invoiced reflects the transportation services rendered. Equipment rental services provide customers with use of either dedicated or nonspecific wellhead proppant delivery equipment solutions for contractual periods defined either through formal lease agreements or executed work orders under established pricing agreements. The amounts invoiced reflect the length of time the equipment set was utilized in the billing period. Contract labor services provide customers with proppant delivery equipment operators through work orders executed under established pricing agreements. The amounts invoiced reflect the amount of time our labor services were utilized in the billing period. We typically invoice our customers on a weekly or monthly basis; however, some customers receive invoices upon well-site operation completion. Standard collection terms are net 30 days, although extended terms are offered in competitive situations. We typically recognize revenue for specific, dedicated equipment set rental arrangements under ASC 842, Leases. For the remaining components of service revenue, we have applied the practical expedient allowed under ASC 606-10-55-18 to recognize transportation revenues in proportion to the amount we have the right to invoice. Contracts with Multiple Performance Obligations From time to time, we may enter into contracts that contain multiple performance obligations, such as work orders containing a combination of product, transportation, equipment rentals, and contract labor services. For these arrangements, we allocate the transaction price to each performance obligation identified in the contract based on relative standalone selling prices, or estimates of such prices, and recognize the related revenue as control of each individual product or service is transferred to the customer, in satisfaction of the corresponding performance obligations. We typically invoice our customers on a weekly or monthly basis; however, some customers received invoices upon well-site operation completion. Standard collection terms are net 30 days, although extended terms are offered in competitive situations. Taxes Collected from Customers and Remitted to Governmental Authorities. We exclude from our measurement of transaction prices all taxes assessed by governmental authorities that are both (i) imposed on and concurrent with a specific revenue-producing transaction and (ii) collected from customers. Accordingly, such tax amounts are not included as a component of net sales or cost of sales. See Note S - Revenue. Deferred Revenues For a limited number of customers, we enter into supply agreements which give customers the right to make advanced payments toward the purchase of certain products at specified volumes over an average initial period of one to fifteen years. These payments represent consideration that is unconditional and for which we have yet to transfer the related product. These payments are recorded as contract liabilities referred to as “deferred revenues” upon receipt and recognized as revenue upon delivery of the related product. Unbilled Receivables Revenues recognized in advance of invoice issuance create assets referred to as “unbilled receivables.” Any portion of our unbilled receivables for which our right to consideration is conditional on a factor other than the passage of time is considered a contract asset. These assets are presented on a combined basis with accounts receivable and are converted to accounts receivable once billed. Debt Issuance Costs We defer costs directly associated with acquiring third-party financing, primarily loan origination costs and related professional expenses. Debt issuance costs are deferred and amortized using the effective interest rate method over the term of our senior secured Term Loan facility and the straight-line method for our Revolver facility. Debt issuance costs related to long-term debt are reflected as a direct deduction from the carrying amount of the debt. See Note J - Debt. Employee Benefit Plans We provide a range of benefits to our employees and retired employees, including pensions and post-retirement healthcare and life insurance benefits. We record annual amounts relating to these plans based on calculations specified by generally accepted accounting principles, which include various actuarial assumptions, including discount rates, assumed rates of returns, compensation increases, turnover rates, mortality tables, and healthcare cost trend rates. We review the actuarial assumptions on an annual basis and make modifications to the assumptions based on current rates and trends when it is deemed appropriate to do so. As required by U.S. generally accepted accounting principles, the effect of the modifications is generally recorded or amortized over future periods. We believe that the assumptions utilized in recording our obligations under the plans are reasonable based on advice from our actuaries and information as to assumptions used by other employers. See Note P - Pension and Post-Retirement Benefits. Environmental Costs Environmental costs, other than qualifying capital expenditures, are accrued at the time the exposure becomes known and costs can be reasonably estimated. Costs are accrued based upon management’s estimates of all direct costs, after taking into account expected reimbursement by third parties (primarily the sellers of acquired businesses) and are reviewed by outside consultants. Environmental costs are charged to expense unless a settlement with an indemnifying party has been reached. Self-Insurance We are self-insured for various levels of employee health insurance coverage, workers’ compensation and third-party product liability claims alleging occupational disease. We purchase insurance coverage for claim amounts which exceed our self-insured retentions. Depending on the type of insurance, these self-insured retentions range from $0.1 million to $0.5 million per occurrence. Our insurance reserves are accrued based on estimates of the ultimate cost of claims expected to occur during the covered period. These estimates are prepared with the assistance of outside actuaries and consultants. Our actuaries periodically review the volume and amount of claims activity, and based upon their findings, we adjust our insurance reserves accordingly. The ultimate cost of claims for a covered period may differ from our original estimates. The current portion of our self-insurance reserves is included in accrued liabilities and the non-current portion is included in other long-term obligations in our Balance Sheets. As of December 31, 2023 and 2022, our self-insurance reserves totaled $5.0 million and $5.6 million, respectively, of which $1.7 million and $1.8 million, respectively, were classified as current. Research and Development Costs We may incur immaterial internal research and development (“R&D”) expenditures, and research and development conducted for others, all of which are expensed as incurred, and included in selling, general and administrative expense. R&D costs may include, but are not limited to, research and administrative salaries, contractor fees, building costs, utilities, administrative expenses, and allocations of corporate costs. Advertising Costs We recognize advertising expense when incurred as selling, general and administrative expense. Advertising costs have not been a significant component of expense for the years ended December 31, 2023, 2022, or 2021. Equity-based Compensation We grant stock options, restricted stock, restricted stock units and performance share units to certain of our employees and directors under the Amended and Restated U.S. Silica Holdings, Inc. 2011 Incentive Compensation Plan. We recognize the cost of employee services rendered in exchange for awards of equity instruments. Vesting of restricted stock and restricted stock units is based on the individual continuing to render service over a pre-defined vesting schedule, generally three years. Cash dividend equivalents are accrued and paid to the holders of time-based restricted stock units and restricted stock. The fair value of the restricted stock awards is equal to the market price of our stock at date of grant. The restricted award-related compensation expense is recognized on a straight-line basis over the vesting period. We grant performance share units to certain employees in which the number of shares of common stock ultimately received is determined based on achievement of certain performance thresholds over a specified performance period (generally three years) in accordance with the stock award agreement. Cash dividend equivalents are not accrued or paid on performance share units. We recognize expense based on the estimated vesting of our performance share units granted and the grant date market price. The estimated vesting of the performance share units is principally based on the probability of achieving certain financial performance levels during the vesting periods. In the period it becomes probable that the minimum performance criteria specified in the award agreement will be achieved, we recognize expense for the proportionate share of the total fair value of the award related to the vesting period that has already lapsed. The remaining fair value of the award is expensed on a straight-line basis over the remaining vesting period. We grant certain employees performance share units, the vesting of which is based on our total shareholder return (“TSR”) ranking among a peer group over a three-year period. The number of units that will vest will depend on the percentage ranking of our TSR compared to the TSRs for each of the companies in the peer group over the performance period. For these awards subject to market conditions, a binomial-lattice model (i.e., Monte Carlo simulation model) is used to fair value these awards at grant date. We also grant certain employees performance share units, the vesting of which is based on adjusted free cash flow ("ACF") targets. The number of ACF measured units that will vest will be based on ACF achievement versus target. The ACF targets are set annually and are approved by the Board of Directors. The related compensation expense is recognized on a straight-line basis over the vesting period. See Note N - Equity-based Compensation. Income Taxes Deferred taxes are recognized on the liability method whereby deferred tax assets are recognized for deductible temporary differences and operating loss and tax credit carry forwards and deferred tax liabilities are recognized for taxable temporary differences. This approach requires recognition of deferred tax liabilities and assets for the expected future tax consequences of events that have been included in the financial statements or tax returns. Under this method, deferred tax liabilities and assets are determined based upon the difference between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the expenses are expected to reverse. Valuation allowances are provided if, based on the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. We recognize a tax benefit associated with an uncertain tax position when, in management’s judgment, it is more likely than not that the position will be sustained upon examination by a taxing authority. For a tax position that meets the more likely than not recognition threshold, we initially and subsequently measure the tax benefit as the largest amount that we judge to have a greater than 50% likelihood of being realized upon ultimate settlement with a taxing authority. The liability associated with unrecognized tax benefits is adjusted periodically due to changing circumstances, such as the progress of tax audits, case law developments and new or emerging legislation. Such adjustments are recognized entirely in the period in which they are identified. The effective tax rate includes the net impact of changes in the liability for unrecognized tax benefits and subsequent adjustments as considered appropriate by management. See Note R - Income Taxes. Financial Instruments We currently use natural gas swaps to manage our exposure to natural gas price increases. Our policy is to not hold or issue derivative financial instruments for trading or speculative purposes. Gains and losses on derivatives designated as cash flow hedges are recorded in other comprehensive income (loss), net of tax, and reclassified to earnings in a manner that matches the timing of the earnings impact of the hedged transactions. The ineffective portion of all hedges, if any, is recognized currently in income. See Note M - Derivative Instruments. Foreign Currency Translation For our operations in countries where the functional currency is other than the U.S. dollar, balance sheet amounts are translated using the exchange rate in effect at the balance sheet date. Income statement amounts are translated monthly using the average exchange rate for the respective month. The gains and losses resulting from the changes in exchange rates from year-to-year are recorded as a component of accumulated other comprehensive income or loss as currency translation adjustments, net of tax. Any gains or losses on transactions in currencies other than the functional currency are included in other income (expense), net, including interest income. Comprehensive Income (loss) In addition to net income (loss), comprehensive income (loss) includes all changes in equity during a period, such as adjustments to minimum pension liabilities and the effective portion of changes in fair value of derivative instruments that qualify as cash flow hedges. Business Combinations We account for business combinations using the acquisition method of accounting. Under this method, acquired assets, including separately identifiable intangible assets and any assumed liabilities, are recorded at their acquisition date estimated fair value. The excess of purchase price over the fair value amounts assigned to the assets acquired and liabilities assumed represents the goodwill amount resulting from the acquisition. Determining the fair value of assets acquired and liabilities assumed involves the use of significant estimates and assumptions. New Accounting Pronouncements Recently Adopted In March 2020, the FASB issued Accounting Standards Update ("ASU") 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting followed by ASU 2021-01, Reference Rate Reform (Topic 848): Scope, issued in January 2021 to provide clarifying guidance regarding the scope of Topic 848. ASU 2020-04 was issued to provide optional guidance for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting. Generally, the guidance is to be applied as of any date from the beginning of an interim period that includes or is subsequent to March 12, 2020, or prospectively from a date within an interim period that includes or is subsequent to March 12, 2020, up to the date that the financial statements are available to be issued. ASU 2020-04 and ASU 2021-01 are effective for all entities through December 31, 2022. In April 2022, the FASB proposed to extend the effective date through December 31, 2024 and affirmed this decision in December 2022. Upon execution of the Fourth Amended and Restated Credit Agreement, we have transitioned from LIBOR. See Note J - Debt for discussion of the Fourth Amended and Restated Credit Agreement. New Accounting Pronouncements Not Yet Adopted In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. The amendments in this Update improve financial reporting by requiring disclosure of incremental segment information on an annual and interim basis for all public entities to enable investors to develop more decision-useful financial analyses. The amendments in this Update do not change or remove current disclosure requirements as required by Topic 280. The amendments in this Update also do not change how a public entity identifies its operating segments, aggregates those operating segments, or applies the quantitative thresholds to determine its reportable segments. The amendments in this Update are effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Public entities will be required to apply the amendments in this Update retrospectively to all prior periods presented in the financial statements. We are currently evaluating the effect this guidance will have on our disclosures. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. The amendments in this Update related to the rate reconciliation and income taxes paid disclosures improve the transparency of income tax disclosures by requiring (1) consistent categories and greater disaggregation of information in the rate reconciliation and (2) income taxes paid disaggregated by jurisdiction. The amendments allow investors to better assess, in their capital allocation decisions, how an entity’s worldwide operations and related tax risks and tax planning and operational opportunities affect its income tax rate and prospects for future cash flows. The other amendments in this Update improve the effectiveness and comparability of disclosures by (1) adding disclosures of pretax income (or loss) and income tax expense (or benefit) to be consistent with U.S. Securities and Exchange Commission (SEC) Regulation S-X 210.4-08(h), Rules of General Application—General Notes to Financial Statements: Income Tax Expense, and (2) removing disclosures that no longer are considered cost beneficial or relevant. The amendments in this Update are effective for annual periods beginning after December 15, 2024. We are currently evaluating the effect this guidance will have on our disclosures.

Pension and Post-Retirement Benefits (Tables)

12 Months Ended

Dec. 31, 2023

Retirement Benefits [Abstract]

Schedule of Net Pension Benefit Cost

Net pension benefit cost (in thousands) consisted of the following:


	Year Ended December 31,
	2023		2022		2021
Service cost	$	2,325	$	2,516	$	2,855
Interest cost	5,343		3,120		2,619
Expected return on plan assets	(6,373)		(5,887)		(5,688)
Settlement loss	1,803		—		—
Net amortization and deferral	41		2,249		3,212
Net pension benefit costs	$	3,139	$	1,998	$	2,998

Net post-retirement benefit cost (in thousands) consisted of the following:


	Year Ended December 31,
	2023		2022		2021
Service cost	$	8	$	18	$	24
Interest cost	332		180		141
Unrecognized prior service cost	(2,063)		—		—
Unrecognized net gain	(792)		(2,360)		(2,204)
Net post-retirement benefit costs	$	(2,515)	$	(2,162)	$	(2,039)

Schedule of Changes in Benefit Obligations and Plan Assets

The changes in benefit obligations and plan assets (in thousands), as well as the funded status (in thousands) of our pension and post-retirement plans were as follows:


	Pension Benefits				Post-retirement Benefits
	2023		2022		2023		2022
Benefit obligation at January 1,	$	112,247	$	144,251	$	7,577	$	9,391
Service cost	2,325		2,516		8		18
Interest cost	5,343		3,120		332		180
Actuarial loss (gain)	2		(28,494)		(552)		(1,566)
Benefits paid	(31,352)		(9,486)		(469)		(504)

Other	74		340		34		58
Benefit obligation at December 31,	$	88,639	$	112,247	$	6,930	$	7,577
Fair value of plan assets at January 1,	$	88,919	$	120,911	$	—	$	—
Actual return on plan assets	7,497		(22,507)		—		—
Employer contributions	2,000		—		435		446
Benefits paid	(31,352)		(9,486)		(469)		(504)
Other	—		1		34		58
Fair value of plan assets at December 31,	$	67,064	$	88,919	$	—	$	—
Plan assets less than benefit obligations at December 31 recognized as liability for pension and other post-retirement benefits	$	(21,575)	$	(23,328)	$	(6,930)	$	(7,577)

Schedule of Estimated Future Pension and Post-Retirement Benefit Payments

Future estimated annual benefit payments (in thousands) for pension and post-retirement benefit obligations were as follows:


	Benefits
			Post-retirement
	Pension		Before Medicare Subsidy		After Medicare Subsidy
2024	$	7,159	$	864	$	864
2025	7,117		776		776
2026	7,145		711		711
2027	7,051		659		659
2028	6,966		596		596
2029-2033	32,951		2,400		2,400

Schedule of Weighted-Average Assumptions Used to Determine Benefit Obligations

The following weighted-average assumptions were used to determine our obligations under the plans:

Pension Benefits

Post-retirement Benefits

2023

2022

2023

2022

Discount rate

5.0

5.2

4.9

5.1

Long-term rate of compensation increase

N/A

Long-term rate of return on plan assets

7.3

6.0%

N/A

Health care cost trend rate:

Pre-65 initial rate/ultimate rate

N/A

7.3%/4.5%

6.8%/4.5%

Pre-65 ultimate year

N/A

2032

2031

Post-65 initial rate/ultimate rate

N/A

N/A/N/A

Post-65 ultimate year

N/A

Schedule of Mortality Tables Used

Mortality tables used for pension benefits and post-retirement benefits plans were the following:


	Pension and Post-retirement Benefits
	2023	2022
Healthy Lives	Pri-2012 base mortality tables with generational mortality improvements using Scale MP-2021	Pri-2012 base mortality tables with generational mortality improvements using Scale MP-2021
Disabled Lives	Pri-2012 base mortality tables with generational mortality improvements using Scale MP-2021	Pri-2012 base mortality tables with generational mortality improvements using Scale MP-2021

Schedule of Major Investments Categories and Their Relative Percentage of the Fair Value to Total Plan Assets

The major investment categories and their relative percentage of the fair value of total plan assets as invested were as follows:


	Pension Benefits				Post-retirement Benefits(1)
	2023		2022		2023		2022
Equity securities	54.1	%	54.3	%	—	%	—	%
Debt securities	43.4	%	44.2	%	—	%	—	%
Cash	2.5	%	1.5	%	—	%	—	%


(1)Retiree health benefits are paid by the Company as covered expenses are incurred.

Schedule of Fair Value of Pension Plan Assets by Asset Category

The fair values of the pension plan assets (in thousands) at December 31, 2023, by asset category, were as follows:


	Level 1		Level 2		Level 3		Total
Cash and cash equivalents	$	—	$	1,652	$	—	$	1,652
Mutual funds:
Diversified emerging markets	2,960		—		—		2,960
Foreign large blend	11,707		—		—		11,707
Large-cap blend	11,685		—		—		11,685
Mid-cap blend	6,763		—		—		6,763
Real estate	3,204		—		—		3,204

Fixed income securities:
Corporate notes and bonds	17,768		—		—		17,768
U.S. Treasuries	5,012		—		—		5,012
Mortgage-backed securities	—		3,250		—		3,250
Asset-backed securities	—		3,063		—		3,063


Net asset	$	59,099	$	7,965	$	—	$	67,064

The fair values of the pension plan assets (in thousands) at December 31, 2022, by asset category, were as follows:


	Level 1		Level 2		Level 3		Total
Cash and cash equivalents	$	—	$	1,362	$	—	$	1,362
Mutual funds:
Diversified emerging markets	4,221		—		—		4,221
Foreign large blend	16,740		—		—		16,740
Large-cap blend	15,464		—		—		15,464
Mid-cap blend	7,720		—		—		7,720
Real assets	4,144		—		—		4,144
Fixed income securities:
Corporate notes and bonds	27,892		—		—		27,892
U.S. Treasuries	5,223		—		—		5,223
Mortgage-backed securities	—		3,000		—		3,000
Asset-backed securities	—		3,153		—		3,153

Net asset	$	81,404	$	7,515	$	—	$	88,919

Schedule of Summary of Multiemployer Pension Plan

A summary of each multiemployer pension plan for which we participate is presented below:

Pension
Fund

EIN/ Pension
Plan No.

Pension Protection Act

Zone Status(1)

FIP/RP Status
Pending/
Implemented

Company
Contributions
(in thousands)

Surcharge
Imposed

Expiration
Date of
CBA

2023

2022

2023

2022

2021

LIUNA

52-6074345/001

Green

406

395

378

6/7/2025

IUOE

36-6052390/001

Green

349

376

328

8/1/2027

CSSS(2)

36-6044243/001

Red

Yes

(1)The Pension Protection Act of 2006 defines the zone status as follows: green—healthy, yellow—endangered, orange—seriously endangered and red—critical.

(2)In 2011, we withdrew from the Central States, Southeast and Southwest Areas Pension Plan. The withdrawal liability of $1.0 million will be paid in monthly installments of approximately $4,000 until 2031.

- Definition

Tabular disclosure of information about multiemployer plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480547/715-80-55-8

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-5

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-5

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-5

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-5

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (e)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-5

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (e)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-5

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (f)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-5

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (f)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-5

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-9

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 80
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480576/715-80-50-9

+ Details

Income Taxes - Income Before Income Tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
United States	$ 172,214	$ 87,686	$ (48,328)
Foreign	23,355	16,313	11,252
Total	$ 195,569	$ 103,999	$ (37,076)

Pension and Post-Retirement Benefits - Weighted-Average Assumptions Used (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Pension Benefits
Pension Plans, Postretirement and Other Employee Benefits
Discount rate	5.00%	5.20%
Long-term rate of return on plan assets	7.30%	6.00%
Post-retirement Benefits
Pension Plans, Postretirement and Other Employee Benefits
Discount rate	4.90%	5.10%
Post-retirement Benefits \| Pre-65
Pension Plans, Postretirement and Other Employee Benefits
Initial rate	7.30%	6.80%
Ultimate rate	4.50%	4.50%

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Schedule of Income before Income Tax, Domestic and Foreign

Income (loss) before income taxes (in thousands) consisted of the following:


	Year ended December 31,
	2023		2022		2021
United States	$	172,214	$	87,686	$	(48,328)
Foreign	23,355		16,313		11,252
Total	$	195,569	$	103,999	$	(37,076)

Schedule of Income Tax Benefit (Expense)

Income tax (expense) benefit (in thousands) consisted of the following:


	Year ended December 31,
	2023		2022		2021
Current:
Federal	$	(6,603)	$	(1,650)	$	—
State	(5,936)		(3,078)		(3,353)
Foreign	(1,230)		(491)		(1,385)
	(13,769)		(5,219)		(4,738)
Deferred:
Federal	(32,972)		(17,881)		7,589
State	(2,339)		(3,059)		(96)
Foreign	—		—		—
	(35,311)		(20,940)		7,493
Income tax (expense) benefit	$	(49,080)	$	(26,159)	$	2,755

Schedule of Effective Income Tax Rate on Pretax Earnings

Income tax (expense) benefit (in thousands) differed from the amount that would be provided by applying the U.S. federal statutory rate due to the following:


	Year ended December 31,
	2023		2022		2021
Income tax (expense) benefit computed at U.S. federal statutory rate	$	(41,069)	$	(21,838)	$	7,786
Decrease (increase) resulting from:
Statutory depletion	3,758		2,963		2,012

Prior year tax return reconciliation	(996)		(1,564)		(2,490)
State income taxes, net of federal benefit	(7,385)		(4,003)		445
Impact of international operations	(854)		(830)		(380)
Unrecognized tax benefits	1,055		(89)		(1,302)

Equity compensation	1,684		(195)		(627)
Executive compensation	(4,963)		(300)		(2,092)
Other, net	(310)		(303)		(597)
Income tax (expense) benefit	$	(49,080)	$	(26,159)	$	2,755

Schedule of Tax Effects on Deferred Tax Assets and Liabilities

The tax effects of the types of temporary differences and carry forwards that gave rise to deferred tax assets and liabilities (in thousands) consisted of the following:


	December 31,
	2023		2022
Gross deferred tax assets:
Net operating loss carry forward and state tax credits	$	23,839	$	54,638
Pension and post-retirement benefit costs	6,214		6,789

Property, plant and equipment	8,210		5,935
Accrued expenses	12,989		18,232
Inventories	369		—
Federal tax credits	—		1,047
Stock-based compensation expense	4,187		6,374
Interest expense limitation	21,685		19,826
Intangibles	4,139		6,366
Lease obligation liability	8,918		11,393
Other	7,406		5,886
Total deferred tax assets	97,956		136,486
Gross deferred tax liabilities:
Land and mineral property basis difference	(130,764)		(124,669)
Fixed assets and depreciation	(67,014)		(74,714)
Inventories	—		(1,170)

Other	(636)		(569)
Total deferred tax liabilities	(198,414)		(201,122)
Net deferred tax liabilities	$	(100,458)	$	(64,636)

Schedule of Unrecognized Tax Benefits Roll Forward

The following table is a reconciliation of our unrecognized tax benefits (in thousands):


	Year ended December 31,
	2023		2022		2021
Balance as of January 1	$	856	$	856	$	—
Additions for tax positions of prior years	—		—		856
Lapse in statute of limitations	(856)		—		—
Balance as of December 31	$	—	$	856	$	856

Commitments and Contingencies - Narrative (Details)		12 Months Ended
Commitments and Contingencies - Narrative (Details)	May 17, 2017 USD ($)	Dec. 31, 2023 USD ($) claim	Dec. 31, 2022 USD ($) claim	Dec. 31, 2021 claim
Loss Contingencies
Purchased reserves	$ 94,400,000
Surety Bonds
Loss Contingencies
Surety bonds outstanding		$ 55,800,000
Reclamation Bonds
Loss Contingencies
Surety bonds outstanding		51,800,000
Other non-current assets
Loss Contingencies
Third party products claims liability under insurance in other long-term obligations		0	$ 0
Other long-term obligations
Loss Contingencies
Third party products claims liability under insurance in other long-term obligations		$ 900,000	$ 800,000
Pending Litigation
Loss Contingencies
Number of new claims filed \| claim		0	0	2
Number of pending claims \| claim		39

Leases - Narrative (Details)	12 Months Ended
Leases - Narrative (Details)	Dec. 31, 2023
Minimum
Lessee, Lease, Description [Line Items]
Remaining term of lease contracts	1 year
Maximum
Lessee, Lease, Description [Line Items]
Remaining term of lease contracts	20 years

Accounts Payable and Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Trade payables	$ 123,667	$ 182,555
Accrued salaries and wages	7,013	10,911
Accrued vacation liability	3,567	3,093
Current portion of liability for pension and post-retirement benefits	986	1,118
Accrued healthcare liability	1,571	1,492
Accrued property taxes and sales taxes	3,422	4,287
Current portion of derivative liability	1,819	2,312
Other accrued liabilities	5,434	10,471
Accounts payable and accrued liabilities	$ 147,479	$ 216,239

Commitments and Contingencies

12 Months Ended

Dec. 31, 2023

Commitments and Contingencies Disclosure [Abstract]

COMMITMENTS AND CONTINGENCIES

NOTE O—COMMITMENTS AND CONTINGENCIES

Future Minimum Annual Commitments (in thousands):


Year ending December 31,	Minimum Purchase Commitments
2024	$	10,124
2025	6,815
2026	4,687
2027	2,288
2028	1,888
Thereafter	5,884
Total future purchase commitments	$	31,686

Minimum Purchase Commitments

We enter into service agreements with our transload and transportation providers as well as commodity suppliers. Some of these agreements require us to purchase a minimum amount of services over a specific period of time. Any inability to meet these minimum contract requirements requires us to pay a shortfall fee, which is based on the difference between the minimum amount contracted for and the actual amount purchased.

Contingent Liability on Royalty Agreement

On May 17, 2017, we purchased reserves in Crane County, Texas, for $94.4 million cash plus contingent consideration. The contingent consideration is a royalty that is based on the tonnage shipped to third-parties. Because the contingent consideration is dependent on future tonnage sold, the amounts of which are uncertain, it is not currently possible to estimate the fair value of these future payments. The contingent consideration will be capitalized at the time a payment is probable and reasonably estimable, and the related depletion expense will be adjusted prospectively.

Other Commitments and Contingencies

Our operating subsidiary, U.S. Silica Company (“U.S. Silica”), has been named as a defendant in various product liability claims alleging silica exposure causing silicosis. During the years ended December 31, 2023, 2022 and 2021, zero, zero and two claims, respectively, were brought against U.S. Silica. As of December 31, 2023, there were 39 active silica-related products liability claims pending in which U.S. Silica is a defendant. Although the outcomes of these claims cannot be predicted with certainty, in the opinion of management, it is not reasonably possible that the ultimate resolution of these matters will have a material adverse effect on our financial position or results of operations that exceeds the accrual amounts.

We have recorded estimated liabilities for these claims in other long-term obligations and an estimate of future recoveries under insurance in other assets on our consolidated balance sheets. As of both December 31, 2023 and 2022, other non-current assets included zero for insurance for third-party products liability claims, and other long-term obligations included $0.9 million and $0.8 million, respectively, for third-party products liability claims.

Obligations Under Guarantees

We have indemnified our insurers against any loss they may incur in the event that holders of surety bonds, issued on our behalf, execute the bonds. As of December 31, 2023, there were $55.8 million in bonds outstanding. The majority of these bonds, $51.8 million, relate to reclamation requirements issued by various government authorities. Reclamation bonds remain outstanding until the mining area is reclaimed and the authority issues a formal release. The remaining bonds relate to licenses, permits, and tax collections.

Accounts Receivable - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Allowance for Doubtful Accounts Receivable Roll Forward
Beginning balance, December 31, 2022	$ 5,691
Allowance for credit losses	(103)	$ 617	$ (455)
Recoveries	95
Write-offs	(360)
Ending balance, December 31, 2023	5,323	5,691
Oil & Gas Proppants
Allowance for Doubtful Accounts Receivable Roll Forward
Beginning balance, December 31, 2022	4,028
Allowance for credit losses	0
Recoveries	95
Write-offs	(300)
Ending balance, December 31, 2023	3,823	4,028
Industrial & Specialty Products
Allowance for Doubtful Accounts Receivable Roll Forward
Beginning balance, December 31, 2022	1,663
Allowance for credit losses	(103)
Recoveries	0
Write-offs	(60)
Ending balance, December 31, 2023	$ 1,500	$ 1,663

Goodwill and Intangible Assets - Estimated Amortization Expense Related to Definite-Lived Intangible Assets (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2024	$ 9,717
2025	9,716
2026	9,716
2027	9,716
2028	$ 9,676

Pension and Post-Retirement Benefits - Summary of Multiemployer Pension Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
LIUNA
Pension Plans, Postretirement and Other Employee Benefits
EIN/ Pension Plan No.	52-6074345/001
Company Contributions (in thousands)	$ 406	$ 395	$ 378
Expiration Date of CBA	Jun. 07, 2025
IUOE
Pension Plans, Postretirement and Other Employee Benefits
EIN/ Pension Plan No.	36-6052390/001
Company Contributions (in thousands)	$ 349	376	328
Expiration Date of CBA	Aug. 01, 2027
CSSS
Pension Plans, Postretirement and Other Employee Benefits
EIN/ Pension Plan No.	36-6044243/001
Company Contributions (in thousands)	$ 51	$ 51	$ 51
Central States, Southeast and Southwest Areas Pension Plan
Pension Plans, Postretirement and Other Employee Benefits
Withdrawal liability from pension plan	1,000
Withdrawal liability paid in monthly installments	$ 4

Organization (Details) - 12 months ended Dec. 31, 2023	yr	segment	Segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of years in business	124
Number of reportable segments		2	2

Audit Information	12 Months Ended
Audit Information	Dec. 31, 2023
Audit Information [Abstract]
Auditor Firm ID	248
Auditor Name	GRANT THORNTON LLP
Auditor Location	Houston, Texas

Parent Company Financials - Condensed Statements of Stockholders' Equity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	$ 704,694	$ 614,083	$ 626,791
Net income (loss)	146,489	77,840	(34,321)
Unrealized gain on derivatives	882	(2,342)	0
Foreign currency translation adjustment	281	(845)	(1,000)
Pension and post-retirement liability	435	1,115	9,828
Cash dividends			(3)
Distributions to non-controlling interest	(1,354)	(1,523)	(1,103)
Equity-based compensation	14,649	18,364	18,809
Proceeds from options exercised		955	105
Shares withheld for tax payments related to vested restricted stock and stock units	(10,549)	(2,953)	(5,023)
Ending Balance	855,527	704,694	614,083
Total U.S. Silica Holdings Inc., Stockholders’ Equity
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	696,685	604,215	615,260
Net income (loss)	146,925	78,176	(33,761)
Unrealized gain on derivatives	882	(2,342)
Foreign currency translation adjustment	281	(845)	(1,000)
Pension and post-retirement liability	435	1,115	9,828
Cash dividends			(3)
Equity-based compensation	14,649	18,364	18,809
Proceeds from options exercised		955	105
Shares withheld for tax payments related to vested restricted stock and stock units	(10,549)	(2,953)	(5,023)
Ending Balance	849,308	696,685	604,215
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	854	845	827
Shares withheld for tax payments related to vested restricted stock and stock units	23	9	18
Ending Balance	877	854	845
Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(186,196)	(186,294)	(181,615)
Proceeds from options exercised		3,051	344
Shares withheld for tax payments related to vested restricted stock and stock units	(10,549)	(2,953)	(5,023)
Ending Balance	(196,745)	(186,196)	(186,294)
Additional Paid-In Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	1,234,834	1,218,575	1,200,023
Equity-based compensation	14,649	18,364	18,809
Proceeds from options exercised		(2,096)	(239)
Shares withheld for tax payments related to vested restricted stock and stock units	(23)	(9)	(18)
Ending Balance	1,249,460	1,234,834	1,218,575
Retained Deficit - Present
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(351,084)	(429,260)	(395,496)
Net income (loss)	146,925	78,176	(33,761)
Cash dividends			(3)
Ending Balance	(204,159)	(351,084)	(429,260)
Accumulated Other Comprehensive (Loss) Income
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(1,723)	349	(8,479)
Unrealized gain on derivatives	882	(2,342)
Foreign currency translation adjustment	281	(845)	(1,000)
Pension and post-retirement liability	435	1,115	9,828
Ending Balance	(125)	(1,723)	349
Non-controlling Interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	8,009	9,868	11,531
Net income (loss)	(436)	(336)	(560)
Distributions to non-controlling interest	(1,354)	(1,523)	(1,103)
Ending Balance	6,219	8,009	9,868
Parent Company
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	704,694	614,083	626,791
Net income (loss)	146,489	77,840	(34,321)
Unrealized gain on derivatives	882	(2,342)	0
Foreign currency translation adjustment	281	(845)	(1,000)
Pension and post-retirement liability	435	1,115	9,828
Cash dividends			(3)
Distributions to non-controlling interest	(1,354)	(1,523)
Equity-based compensation	14,649	18,364	18,809
Proceeds from options exercised		955	105
Shares withheld for tax payments related to vested restricted stock and stock units	(10,549)	(2,953)	(5,023)
Ending Balance	855,527	704,694	614,083
Parent Company \| Total U.S. Silica Holdings Inc., Stockholders’ Equity
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	696,685	604,215	615,260
Net income (loss)	146,925	78,176	(33,761)
Unrealized gain on derivatives	882	(2,342)
Foreign currency translation adjustment	281	(845)	(1,000)
Pension and post-retirement liability	435	1,115	9,828
Cash dividends			(3)
Equity-based compensation	14,649	18,364	18,809
Proceeds from options exercised		955	105
Shares withheld for tax payments related to vested restricted stock and stock units	(10,549)	(2,953)	(5,023)
Ending Balance	849,308	696,685	604,215
Parent Company \| Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	854	845	827
Shares withheld for tax payments related to vested restricted stock and stock units	23	9	18
Ending Balance	877	854	845
Parent Company \| Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(186,196)	(186,294)	(181,615)
Proceeds from options exercised		3,051	344
Shares withheld for tax payments related to vested restricted stock and stock units	(10,549)	(2,953)	(5,023)
Ending Balance	(196,745)	(186,196)	(186,294)
Parent Company \| Additional Paid-In Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	1,234,834	1,218,575	1,200,023
Equity-based compensation	14,649	18,364	18,809
Proceeds from options exercised		(2,096)	(239)
Shares withheld for tax payments related to vested restricted stock and stock units	(23)	(9)	(18)
Ending Balance	1,249,460	1,234,834	1,218,575
Parent Company \| Retained Deficit - Present
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(351,084)	(429,260)	(395,496)
Net income (loss)	146,925	78,176	(33,761)
Cash dividends			(3)
Ending Balance	(204,159)	(351,084)	(429,260)
Parent Company \| Accumulated Other Comprehensive (Loss) Income
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(1,723)	349	(8,479)
Unrealized gain on derivatives	882	(2,342)
Foreign currency translation adjustment	281	(845)	(1,000)
Pension and post-retirement liability	435	1,115	9,828
Ending Balance	(125)	(1,723)	349
Parent Company \| Non-controlling Interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	8,009	9,868	11,531
Net income (loss)	(436)	(336)	(560)
Distributions to non-controlling interest	(1,354)	(1,523)
Ending Balance	$ 6,219	$ 8,009	$ 9,868

Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Inventory Disclosure [Abstract]
Supplies	$ 65,422	$ 54,805
Raw materials and work in process	54,142	47,042
Finished goods	29,865	45,779
Total inventories	$ 149,429	$ 147,626

Property, Plant and Mine Development (Tables)

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment [Abstract]

Schedule of Property, Plant and Mine Development

Property, plant and mine development (in thousands) consisted of the following:


	December 31, 2023		December 31, 2022
Mining property and mine development	$	793,582	$	789,601
Asset retirement cost	14,728		8,869
Land	53,100		53,128
Land improvements	87,618		76,456
Buildings	76,691		73,151
Machinery and equipment	1,253,734		1,217,933
Furniture and fixtures	2,841		3,922
Construction-in-progress	54,186		55,696
	2,336,480		2,278,756
Accumulated depletion, depreciation, amortization and impairment charges	(1,211,260)		(1,099,922)
Total property, plant and mine development, net	$	1,125,220	$	1,178,834

Equity-Based Compensation - Performance Share Unit Activity (Details) - Performance Share Units - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Number of Shares
Unvested balance at the beginning (in shares)	2,292,751
Granted (in shares)	1,295,904	920,681	886,091
Vested (in shares)	(1,549,033)
Forfeited/Cancelled (in shares)	(165,562)
Unvested balance at the ending (in shares)	1,874,060	2,292,751
Weighted Average
Unvested balance at the beginning (in dollars per share)	$ 9.51
Granted (dollars per share)	9.54	$ 11.79	$ 12.04
Vested (in dollars per share)	6.60
Forfeited/Cancelled (in dollars per share)	11.76
Unvested balance at the end (in dollars per share)	$ 11.73	$ 9.51

Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Numerator:
Net income (loss) attributable to U.S. Silica Holdings, Inc.	$ 146,925	$ 78,176	$ (33,761)
Net income (loss) attributable to U.S. Silica Holdings, Inc.	$ 146,925	$ 78,176	$ (33,761)
Denominator:
Weighted average shares outstanding, basic (shares)	76,980	75,512	74,350
Diluted effect of stock awards (shares)	1,540	2,158	0
Weighted average shares outstanding assuming dilution (shares)	78,520	77,670	74,350
Earnings (loss) per share attributable to U.S. Silica Holdings, Inc.:
Basic earnings (loss) per share (in dollars per share)	$ 1.91	$ 1.04	$ (0.45)
Diluted earnings (loss) per share (in dollars per share)	$ 1.87	$ 1.01	$ (0.45)

Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2023

Earnings Per Share [Abstract]

Schedule of Computation of Basic and Diluted Earnings Per Share

The following table shows the computation of basic and diluted earnings per share:


In thousands, except per share amounts	Year ended December 31,
	2023		2022		2021
Numerator:
Net income (loss) attributable to U.S. Silica Holdings, Inc.	$	146,925	$	78,176	$	(33,761)

Denominator:
Weighted average shares outstanding	76,980		75,512		74,350
Diluted effect of stock awards	1,540		2,158		—
Weighted average shares outstanding assuming dilution	78,520		77,670		74,350

Earnings (loss) per share attributable to U.S. Silica Holdings, Inc.:
Basic earnings (loss) per share	$	1.91	$	1.04	$	(0.45)
Diluted earnings (loss) per share	$	1.87	$	1.01	$	(0.45)

Schedule of Antidilutive Securities Excluded from Computation of Diluted Earnings (Loss) Per Common Share

Certain stock options, restricted stock awards and performance share units were excluded from the computation of diluted earnings per share because their effect would have been anti-dilutive. Such potentially dilutive shares and stock awards (in thousands) excluded from the calculation of diluted earnings (loss) per common share were as follows:


	Year ended December 31,
	2023	2022	2021
Potentially dilutive shares excluded	—	—	1,714
Stock options excluded	349	509	667
Restricted stock and performance share units awards excluded	48	36	66

Leases (Tables)

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

Schedule of Supplemental Balance Sheet Information

Supplemental balance sheet information related to leases (in thousands except for term and rate information) was as follows:


Leases	Classification	December 31, 2023		December 31, 2022
Assets
Operating	Lease right-of-use assets	$	37,890	$	39,088
Finance	Lease right-of-use assets	3,205		3,286
Total leased assets		$	41,095	$	42,374
Liabilities
Current
Operating	Current portion of operating lease liabilities	$	18,569	$	19,773
Finance	Current portion of long-term debt	1,147		1,107
Non-Current
Operating	Operating lease liabilities	55,089		64,478
Finance	Long-term debt, net	1,961		2,153
Total lease liabilities		$	76,766	$	87,511

Operating lease liabilities are based on the net present value of the remaining lease payments over the remaining lease term. As most of our leases do not provide an implicit rate, in determining the lease liability and the present value of lease payments, we used our incremental borrowing rate based on the information available at the lease commencement date. The weighted average remaining lease term and discount rate related to leases were as follows:


Lease Term and Discount Rate	December 31, 2023		December 31, 2022
Weighted average remaining lease term:
Operating leases	6.2 years		6.4 years
Finance leases	4.8 years		4.4 years

Weighted average discount rate:
Operating leases	6.3	%	5.7	%
Finance leases	6.6	%	5.1	%

Schedule of Components of Lease Expense and Supplemental Cash Flow Information

The components of lease expense included in our Consolidated Statements of Operations were as follows:


Lease Costs	Classification	Year Ended December 31, 2023		Year Ended December 31, 2022
Operating lease costs (1)	Cost of Sales	$	37,648	$	38,576
Operating lease costs (2)	Selling, general, and administrative	2,539		1,641

Total (3)		$	40,187	$	40,217

(1) Included short-term operating lease costs of $23.3 million and $23.5 million for the years ended December 31, 2023 and 2022, respectively.

(2) Included short-term operating lease costs of $1.2 million and $0.5 million for the years ended December 31, 2023 and 2022, respectively.

(3) Does not include expense of $0.9 million and $1.5 million for the years ended December 31, 2023 and 2022 for finance leases.

Supplemental cash flow information related to leases was as follows:


	Year Ended December 31, 2023		Year Ended December 31, 2022
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows for operating leases	$	25,541	$	22,410
Financing cash flows for finance leases	$	1,009	$	1,576

Right-of-use assets obtained in exchange for new lease liabilities:
Operating leases	$	4,768	$	14,744
Finance leases	$	1,626	$	2,536

Schedule of Maturity of Operating Lease Liabilities

Maturities of lease liabilities as of December 31, 2023:


Maturities of lease liabilities	Operating leases		Finance leases
2024	$	23,405	$	1,342
2025	17,252		1,060
2026	13,172		896
2027	9,413		46
2028	7,171		46
Thereafter	21,727		144
Total lease payments	$	92,140	$	3,534
Less: Interest	16,714		426
Less: Other operating expenses	1,768		—
Total	$	73,658	$	3,108

Schedule of Maturities of Finance Lease Liabilities

Maturities of lease liabilities as of December 31, 2023:


Maturities of lease liabilities	Operating leases		Finance leases
2024	$	23,405	$	1,342
2025	17,252		1,060
2026	13,172		896
2027	9,413		46
2028	7,171		46
Thereafter	21,727		144
Total lease payments	$	92,140	$	3,534
Less: Interest	16,714		426
Less: Other operating expenses	1,768		—
Total	$	73,658	$	3,108

Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Tax expense (benefit) on unrealized gain (loss) on derivatives	$ 281	$ (746)	$ 0
Tax expense (benefit) on foreign currency translation adjustment	90	(269)	(309)
Tax (expense) benefit on pension and other post-retirement benefits liability adjustment	$ 139	$ 355	$ 3,131

Equity-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Schedule of Stock Options Activity

The following table summarizes the status of, and changes in, our stock option awards:


	Number of Shares	Weighted Average Exercise Price		Aggregate Intrinsic Value		Weighted Average Remaining Contractual Term in Years
Outstanding at December 31, 2022	508,523	$	36.22	$	—	2.0 years
Granted	—	$	—	$	—
Exercised	—	$	—	$	—
Forfeited	(122,009)	$	36.79	$	—
Expired	(37,434)	$	24.80	$	—
Outstanding at December 31, 2023	349,080	$	37.24	$	—	1.1 years
Exercisable at December 31, 2023	349,080	$	37.24	$	—	1.1 years

The following table summarizes stock option exercise activity:


	As of December 31,
	2023		2022		2021
Options exercised (in actual shares)	—		90,000		10,164
Intrinsic value of options exercised (in thousands)	$	—	$	613	$	44
Cash received from options exercised (in thousands)	$	—	$	955	$	105
Tax benefit realized from options exercised (in thousands)	$	—	$	148	$	11

Schedule of Restricted Stock, Restricted Stock Unit and Performance Share Unit Awards Activity

The following table summarizes the status of, and changes in, our unvested restricted stock awards:


	Number of Shares	Grant Date Weighted Average Fair Value
Unvested, December 31, 2022	1,438,386	$	9.37
Granted	776,339	$	12.16
Vested	(792,727)	$	9.00
Forfeited	(168,019)	$	9.41
Unvested, December 31, 2023	1,253,979	$	11.33

The following table summarizes the status of, and changes in, our performance share unit awards:


	Number of Shares	Grant Date Weighted Average Fair Value
Unvested, December 31, 2022	2,292,751	$	9.51
Granted	1,295,904	$	9.54
Vested	(1,549,033)	$	6.60
Forfeited/Cancelled	(165,562)	$	11.76
Unvested, December 31, 2023	1,874,060	$	11.73

Leases

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

LEASES

NOTE Q— LEASES

We lease railroad cars, office space, mining property, mining/processing equipment, and transportation and other equipment. The majority of our leases have remaining lease terms of approximately one year to 20 years. Our lease terms may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. We have lease agreements with lease and non-lease components, the latter of which are generally accounted for separately.

Supplemental balance sheet information related to leases (in thousands except for term and rate information) was as follows:


Leases	Classification	December 31, 2023		December 31, 2022
Assets
Operating	Lease right-of-use assets	$	37,890	$	39,088
Finance	Lease right-of-use assets	3,205		3,286
Total leased assets		$	41,095	$	42,374
Liabilities
Current
Operating	Current portion of operating lease liabilities	$	18,569	$	19,773
Finance	Current portion of long-term debt	1,147		1,107
Non-Current
Operating	Operating lease liabilities	55,089		64,478
Finance	Long-term debt, net	1,961		2,153
Total lease liabilities		$	76,766	$	87,511


Lease Term and Discount Rate	December 31, 2023		December 31, 2022
Weighted average remaining lease term:
Operating leases	6.2 years		6.4 years
Finance leases	4.8 years		4.4 years

Weighted average discount rate:
Operating leases	6.3	%	5.7	%
Finance leases	6.6	%	5.1	%

The components of lease expense included in our Consolidated Statements of Operations were as follows:


Lease Costs	Classification	Year Ended December 31, 2023		Year Ended December 31, 2022
Operating lease costs (1)	Cost of Sales	$	37,648	$	38,576
Operating lease costs (2)	Selling, general, and administrative	2,539		1,641

Total (3)		$	40,187	$	40,217

(1) Included short-term operating lease costs of $23.3 million and $23.5 million for the years ended December 31, 2023 and 2022, respectively.

(2) Included short-term operating lease costs of $1.2 million and $0.5 million for the years ended December 31, 2023 and 2022, respectively.

(3) Does not include expense of $0.9 million and $1.5 million for the years ended December 31, 2023 and 2022 for finance leases.

Supplemental cash flow information related to leases was as follows:


	Year Ended December 31, 2023		Year Ended December 31, 2022
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows for operating leases	$	25,541	$	22,410
Financing cash flows for finance leases	$	1,009	$	1,576

Right-of-use assets obtained in exchange for new lease liabilities:
Operating leases	$	4,768	$	14,744
Finance leases	$	1,626	$	2,536

Maturities of lease liabilities as of December 31, 2023:


Maturities of lease liabilities	Operating leases		Finance leases
2024	$	23,405	$	1,342
2025	17,252		1,060
2026	13,172		896
2027	9,413		46
2028	7,171		46
Thereafter	21,727		144
Total lease payments	$	92,140	$	3,534
Less: Interest	16,714		426
Less: Other operating expenses	1,768		—
Total	$	73,658	$	3,108

LEASES

NOTE Q— LEASES

Supplemental balance sheet information related to leases (in thousands except for term and rate information) was as follows:


Leases	Classification	December 31, 2023		December 31, 2022
Assets
Operating	Lease right-of-use assets	$	37,890	$	39,088
Finance	Lease right-of-use assets	3,205		3,286
Total leased assets		$	41,095	$	42,374
Liabilities
Current
Operating	Current portion of operating lease liabilities	$	18,569	$	19,773
Finance	Current portion of long-term debt	1,147		1,107
Non-Current
Operating	Operating lease liabilities	55,089		64,478
Finance	Long-term debt, net	1,961		2,153
Total lease liabilities		$	76,766	$	87,511


Lease Term and Discount Rate	December 31, 2023		December 31, 2022
Weighted average remaining lease term:
Operating leases	6.2 years		6.4 years
Finance leases	4.8 years		4.4 years

Weighted average discount rate:
Operating leases	6.3	%	5.7	%
Finance leases	6.6	%	5.1	%

The components of lease expense included in our Consolidated Statements of Operations were as follows:


Lease Costs	Classification	Year Ended December 31, 2023		Year Ended December 31, 2022
Operating lease costs (1)	Cost of Sales	$	37,648	$	38,576
Operating lease costs (2)	Selling, general, and administrative	2,539		1,641

Total (3)		$	40,187	$	40,217

(1) Included short-term operating lease costs of $23.3 million and $23.5 million for the years ended December 31, 2023 and 2022, respectively.

(2) Included short-term operating lease costs of $1.2 million and $0.5 million for the years ended December 31, 2023 and 2022, respectively.

(3) Does not include expense of $0.9 million and $1.5 million for the years ended December 31, 2023 and 2022 for finance leases.

Supplemental cash flow information related to leases was as follows:


	Year Ended December 31, 2023		Year Ended December 31, 2022
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows for operating leases	$	25,541	$	22,410
Financing cash flows for finance leases	$	1,009	$	1,576

Right-of-use assets obtained in exchange for new lease liabilities:
Operating leases	$	4,768	$	14,744
Finance leases	$	1,626	$	2,536

Maturities of lease liabilities as of December 31, 2023:


Maturities of lease liabilities	Operating leases		Finance leases
2024	$	23,405	$	1,342
2025	17,252		1,060
2026	13,172		896
2027	9,413		46
2028	7,171		46
Thereafter	21,727		144
Total lease payments	$	92,140	$	3,534
Less: Interest	16,714		426
Less: Other operating expenses	1,768		—
Total	$	73,658	$	3,108

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Total U.S. Silica Holdings Inc., Stockholders’ Equity	Common Stock	Treasury Stock	Additional Paid-In Capital	Retained Deficit	Accumulated Other Comprehensive (Loss) Income	Non-controlling Interest
Beginning Balance at Dec. 31, 2020	$ 626,791	$ 615,260	$ 827	$ (181,615)	$ 1,200,023	$ (395,496)	$ (8,479)	$ 11,531
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(34,321)	(33,761)				(33,761)		(560)
Unrealized gain on derivatives	0
Foreign currency translation adjustment	(1,000)	(1,000)					(1,000)
Pension and post-retirement liability	9,828	9,828					9,828
Cash dividends	(3)	(3)				(3)
Distributions to non-controlling interest	(1,103)							(1,103)
Common stock-based compensation plans activity:
Equity-based compensation	18,809	18,809			18,809
Proceeds from options exercised	105	105		344	(239)
Shares withheld for tax payments related to vested restricted stock and stock units	(5,023)	(5,023)	18	(5,023)	(18)
Ending Balance at Dec. 31, 2021	614,083	604,215	845	(186,294)	1,218,575	(429,260)	349	9,868
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	77,840	78,176				78,176		(336)
Unrealized gain on derivatives	(2,342)	(2,342)					(2,342)
Foreign currency translation adjustment	(845)	(845)					(845)
Pension and post-retirement liability	1,115	1,115					1,115
Distributions to non-controlling interest	(1,523)							(1,523)
Common stock-based compensation plans activity:
Equity-based compensation	18,364	18,364			18,364
Proceeds from options exercised	955	955		3,051	(2,096)
Shares withheld for tax payments related to vested restricted stock and stock units	(2,953)	(2,953)	9	(2,953)	(9)
Ending Balance at Dec. 31, 2022	704,694	696,685	854	(186,196)	1,234,834	(351,084)	(1,723)	8,009
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	146,489	146,925				146,925		(436)
Unrealized gain on derivatives	882	882					882
Foreign currency translation adjustment	281	281					281
Pension and post-retirement liability	435	435					435
Distributions to non-controlling interest	(1,354)							(1,354)
Common stock-based compensation plans activity:
Equity-based compensation	14,649	14,649			14,649
Shares withheld for tax payments related to vested restricted stock and stock units	(10,549)	(10,549)	23	(10,549)	(23)
Ending Balance at Dec. 31, 2023	$ 855,527	$ 849,308	$ 877	$ (196,745)	$ 1,249,460	$ (204,159)	$ (125)	$ 6,219

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock authorized (shares)	10,000,000	10,000,000
Preferred stock issued (shares)	0	0
Preferred stock outstanding (shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock authorized (shares)	500,000,000	500,000,000
Common stock issued (shares)	87,970,110	85,631,109
Common stock outstanding (shares)	77,192,239	75,738,512
Treasury stock, at cost (shares)	10,777,871	9,892,597

Equity-Based Compensation - Restricted Stock and Restricted Stock Units Activity (Details) - Restricted Stock and Restricted Stock Units - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Number of Shares
Unvested balance at the beginning (in shares)	1,438,386
Granted (in shares)	776,339	728,357	881,261
Vested (in shares)	(792,727)
Forfeited/Cancelled (in shares)	(168,019)
Unvested balance at the ending (in shares)	1,253,979	1,438,386
Grant Date Weighted Average Fair Value
Unvested balance at the beginning (in dollars per share)	$ 9.37
Granted (dollars per share)	12.16
Vested (in dollars per share)	9.00
Forfeited/Cancelled (in dollars per share)	9.41
Unvested balance at the end (in dollars per share)	$ 11.33	$ 9.37

Segment Reporting - Narrative (Details)	12 Months Ended
Segment Reporting - Narrative (Details)	Dec. 31, 2023 USD ($) segment	Dec. 31, 2023 USD ($) Segment	Dec. 31, 2023 USD ($) product	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Segment Reporting Information
Number of reportable segments	2	2
Number of product types \| product			800
Goodwill	$ 185,649,000	$ 185,649,000	$ 185,649,000	$ 185,649,000	$ 185,649,000
Oil & Gas Proppants
Segment Reporting Information
Goodwill	0	0	0	0	0
Industrial & Specialty Products
Segment Reporting Information
Goodwill	$ 185,649,000	$ 185,649,000	$ 185,649,000	$ 185,649,000	$ 185,649,000

- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References + Details

Revenue

12 Months Ended

Dec. 31, 2023

Revenue from Contract with Customer [Abstract]

REVENUE

NOTE S— REVENUE

We consider sales disaggregated at the product and service level by business segment to depict how the nature, amount, timing and uncertainty of revenues and cash flow are impacted by changes in economic factors. The following table reflects our sales disaggregated by major source (in thousands):


	Year Ended December 31, 2023						Year Ended December 31, 2022
Category	Oil & Gas Proppants		Industrial & Specialty Products		Total Sales		Oil & Gas Proppants		Industrial & Specialty Products		Total Sales
Product	$	673,848	$	557,746	$	1,231,594	$	576,293	$	563,480	$	1,139,773
Service	320,428		—		320,428		385,374		—		385,374
Total Sales	$	994,276	$	557,746	$	1,552,022	$	961,667	$	563,480	$	1,525,147

The following tables reflect the changes in our contract assets, which we classify as unbilled receivables and our contract liabilities, which we classify as deferred revenues (in thousands):


	Unbilled Receivables
	December 31, 2023		December 31, 2022
Beginning Balance	$	—	$	1,957
Reclassifications to billed receivables	—		(4,457)
Revenues recognized in excess of period billings	—		2,500
Ending Balance	$	—	$	—

We enter into certain customer supply agreements which give the customers the right to purchase certain products for a discounted price at certain volumes over an average initial contract term of one to fifteen years. The advance payments represent future purchases and are recorded as deferred revenue, recognized as revenue over the contract term of each supply agreement.


	Deferred Revenue
	December 31, 2023		December 31, 2022
Beginning Balance	$	30,752	$	20,741
Revenues recognized from balances held at the beginning of the period	(15,370)		(3,905)
Revenues deferred from period collections on unfulfilled performance obligations	130		27,398
Revenues recognized from period collections	—		(13,482)
Ending Balance	$	15,512	$	30,752

We have elected to use the practical expedients allowed under ASC 606-10-50-14, pursuant to which we have excluded disclosures of transaction prices allocated to remaining performance obligations and when we expect to recognize such revenue. The majority of our remaining performance obligations are primarily comprised of unfulfilled product, transportation service, and labor service orders, all of which hold a remaining duration of less than one year. The long term portion of deferred revenue primarily represents a combination of refundable and nonrefundable customer prepayments for which related current performance obligations do not yet exist, but are expected to arise, before the expiration of the contract. Our residual unfulfilled performance obligations are comprised primarily of long-term equipment rental arrangements in which we recognize revenues equal to what we have a right to invoice. Generally, no variable consideration exists related to our remaining performance obligations and no consideration is excluded from the associated transaction prices.

Foreign Operations

The following table includes information related to our foreign operations (in thousands):


	For the years ended
	December 31, 2023		December 31, 2022		December 31, 2021
Total Sales	$	110,107	$	112,753	$	96,317
Pre-tax income	$	23,355	$	16,313	$	11,252
Net income	$	18,450	$	12,887	$	8,889

Foreign operations constituted approximately $23.1 million and $33.4 million of consolidated assets as of December 31, 2023 and 2022, respectively.

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-9

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
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-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-10

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
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-Name Accounting Standards Codification
-Section 50
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-URI https://asc.fasb.org//1943274/2147479806/606-10-50-15

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
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-Section 50
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-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
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-Section 50
-Paragraph 13
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-13

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Topic 606
-Publisher FASB
-URI https://asc.fasb.org//606/tableOfContent

+ Details

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating activities:
Net income	$ 146,489	$ 77,840	$ (34,321)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation, depletion and amortization	137,259	140,166	161,131
Goodwill and other asset impairments	0	0	202
Debt issuance amortization	3,105	4,815	5,059
Original issue discount amortization	3,353	974	1,026
Deferred income taxes	35,311	20,940	(7,493)
Deferred revenue	(15,734)	(15,801)	(18,158)
Gain on disposal of property, plant and equipment	(17,951)	(1,005)	(131)
Equity-based compensation	14,649	18,364	18,809
Allowance for credit losses, net of recoveries	(103)	617	(455)
Other	23,962	11,959	28,632
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable	22,817	(8,075)	5,026
Inventories	(1,688)	(31,209)	(11,029)
Prepaid expenses and other current assets	10,206	6,277	12,371
Income taxes	182	(1,072)	1,828
Accounts payable and accrued liabilities	(65,916)	67,576	48,709
Operating lease liabilities	(25,541)	(22,410)	(24,451)
Liability for pension and other post-retirement benefits	(2,328)	(2,134)	(15,341)
Other noncurrent assets and liabilities	(4,204)	(5,106)	(2,067)
Net cash provided by operating activities	263,868	262,716	169,347
Investing activities:
Capital expenditures	(65,155)	(53,168)	(30,307)
Capitalized intellectual property costs	(315)	(394)	(210)
Proceeds from sale of property, plant and equipment	20,749	2,609	661
Net cash used in investing activities	(44,721)	(50,953)	(29,856)
Financing activities:
Dividends paid	(23)	(164)	(26)
Proceeds from options exercised	0	955	105
Tax payments related to shares withheld for vested restricted stock and stock units	(10,549)	(2,953)	(5,023)
Payments on draw down on the Revolver	0	0	(25,000)
Payments on short-term debt	(8,863)	(7,237)	(6,398)
Payments on long-term debt	(190,999)	(158,064)	(12,800)
Financing fees paid	(41,649)	0	0
Distributions to non-controlling interest	(1,354)	(1,523)	(1,103)
Principal payments on finance lease obligations	(839)	(1,357)	(741)
Net cash used in financing activities	(254,276)	(170,343)	(50,986)
Net (decrease) increase in cash and cash equivalents	(35,129)	41,420	88,505
Cash and cash equivalents, beginning of period	280,845	239,425	150,920
Cash and cash equivalents, end of period	245,716	280,845	239,425
Cash paid (received) during the period for:
Interest	95,133	71,235	64,650
Taxes, net of refunds	13,923	(14,809)	(12,994)
Non-cash Items:
Net assets assumed in business acquisition	0	0	68
Accrued capital expenditures	$ 1,632	$ 6,175	$ 1,196

Property, Plant and Mine Development (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment
Property, plant and mine development, gross	$ 2,336,480	$ 2,278,756
Accumulated depletion, depreciation, amortization and impairment charges	(1,211,260)	(1,099,922)
Total property, plant and mine development, net	1,125,220	1,178,834
Mining property and mine development
Property, Plant and Equipment
Property, plant and mine development, gross	793,582	789,601
Asset retirement cost
Property, Plant and Equipment
Property, plant and mine development, gross	14,728	8,869
Land
Property, Plant and Equipment
Property, plant and mine development, gross	53,100	53,128
Land improvements
Property, Plant and Equipment
Property, plant and mine development, gross	87,618	76,456
Buildings
Property, Plant and Equipment
Property, plant and mine development, gross	76,691	73,151
Machinery and equipment
Property, Plant and Equipment
Property, plant and mine development, gross	1,253,734	1,217,933
Furniture and fixtures
Property, Plant and Equipment
Property, plant and mine development, gross	2,841	3,922
Construction-in-progress
Property, Plant and Equipment
Property, plant and mine development, gross	$ 54,186	$ 55,696

Inventories

12 Months Ended

Dec. 31, 2023

Inventory Disclosure [Abstract]

INVENTORIES

NOTE F—INVENTORIES

Inventories (in thousands) consisted of the following:


	December 31, 2023		December 31, 2022
Supplies	$	65,422	$	54,805
Raw materials and work in process	54,142		47,042
Finished goods	29,865		45,779
Total inventories	$	149,429	$	147,626

Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Total lease costs	$ 40,187	$ 40,217
Finance lease expense	900	1,500
Cost of Sales
Lessee, Lease, Description [Line Items]
Total lease costs	37,648	38,576
Short-term operating lease costs	23,300	23,500
Selling, general, and administrative
Lessee, Lease, Description [Line Items]
Total lease costs	2,539	1,641
Short-term operating lease costs	$ 1,200	$ 500

Related Party Transactions	12 Months Ended
Related Party Transactions	Dec. 31, 2023
Related Party Transactions [Abstract]
RELATED PARTY TRANSACTIONS	NOTE T— RELATED PARTY TRANSACTIONS There were no related party transactions during the years ended December 31, 2023, 2022 or 2021.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-5

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-6

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(g)(3))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(c))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(e))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
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-URI https://asc.fasb.org//850/tableOfContent

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
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-Name Accounting Standards Codification
-Section 50
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-URI https://asc.fasb.org//1943274/2147483326/850-10-50-6

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
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-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

+ Details

Derivative Instruments - Estimated Fair Values of Derivative Instruments (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) MMBTU	Dec. 31, 2022 USD ($)
Natural Gas - W. Texas (WAHA) - Inside FERC
Derivative Instruments, Gain (Loss)
Contract/Notional Amount (MMBtu) \| MMBTU	1,200,000
Contract/Notional Amount		$ 1,200
Carrying Amount	$ 0	(1,887)
Fair Value	$ 0	(1,887)
Natural Gas - W. Texas (WAHA) - Inside FERC
Derivative Instruments, Gain (Loss)
Contract/Notional Amount (MMBtu) \| MMBTU	870,000
Contract/Notional Amount		870
Carrying Amount	$ (1,542)	(656)
Fair Value	$ (1,542)	(656)
Natural Gas - W. Texas (WAHA) - Inside FERC
Derivative Instruments, Gain (Loss)
Contract/Notional Amount (MMBtu) \| MMBTU	750,000
Carrying Amount	$ (11)	0
Fair Value	$ (11)	0
Natural Gas - Henry Hub - NYMEX
Derivative Instruments, Gain (Loss)
Contract/Notional Amount (MMBtu) \| MMBTU	300,000
Contract/Notional Amount		300
Carrying Amount	$ 0	(425)
Fair Value	$ 0	(425)
Natural Gas - Henry Hub - NYMEX
Derivative Instruments, Gain (Loss)
Contract/Notional Amount (MMBtu) \| MMBTU	120,000
Contract/Notional Amount		120
Carrying Amount	$ (258)	(85)
Fair Value	$ (258)	(85)
Natural Gas - Henry Hub - NYMEX
Derivative Instruments, Gain (Loss)
Contract/Notional Amount (MMBtu) \| MMBTU	90,000
Contract/Notional Amount		90
Carrying Amount	$ (115)	(35)
Fair Value	$ (115)	$ (35)

Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The accompanying Consolidated Financial Statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”). In the opinion of management, all adjustments necessary for a fair presentation of the Consolidated Financial Statements have been included. Such adjustments are of a normal, recurring nature. Throughout this report we refer to (i) our Consolidated Balance Sheets as our “Balance Sheets,” (ii) our Consolidated Statements of Operations as our “Income Statements,” and (iii) our Consolidated Statements of Cash Flows as our “Cash Flows.”
Consolidation	Consolidation The Consolidated Financial Statements include the accounts of Holdings and its direct and indirect wholly-owned subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation.
Use of Estimates and Assumptions	Use of Estimates and Assumptions The preparation of Consolidated Financial Statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the related disclosure of contingent assets and liabilities at the date of the Consolidated Financial Statements and the reported amounts of revenues and expenses during the reporting period. The areas requiring the use of management estimates and assumptions relate to the purchase price allocation for businesses acquired; mineral reserves that are the basis for future cash flow estimates utilized in impairment calculations and units-of-production amortization calculations; environmental, reclamation and closure obligations; estimates of recoverable minerals; estimates of allowance for credit losses; estimates of fair value for certain reporting units and asset impairments (including impairments of goodwill, intangible assets and other long-lived assets); write-downs of inventory to net realizable value; equity-based compensation expense; post-employment, post-retirement and other employee benefit liabilities; valuation allowances for deferred tax assets; contingent considerations; reserves for contingencies and litigation and the fair value and accounting treatment of financial instruments. We base our estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances. Accordingly, actual results may differ significantly from these estimates under different assumptions or conditions.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents consist of all highly liquid investments with a maturity of three months or less when purchased. Because of the short maturity of these investments, the carrying amounts approximate their fair value. Cash and cash equivalents are invested primarily in money market securities held by financial institutions with high credit ratings. Accounts at each institution are insured by the Federal Deposit Insurance Corporation. Cash balances at times may exceed federally-insured limits. We have not experienced any losses in such accounts and believe we are not exposed to any significant credit risk on cash.
Accounts Receivables	Accounts Receivable The majority of our accounts receivable are due from companies in the oil and natural gas drilling, building and construction products, filler and extenders, filtration, glass, absorbents, sports and recreation, foundry and other major industries. Credit is extended based on evaluation of a customer’s financial condition and, generally, collateral is not required. Accounts receivable are stated at amounts due from customers net of allowance for credit losses. Accounts outstanding longer than the payment terms are considered past due. We determine our allowance by considering a number of factors, including the length of time trade accounts receivable are past due, our previous loss history, the customer’s current ability to pay its obligation to us and the condition of the general economy and the industry as a whole. Ongoing credit evaluations are performed. We write-off accounts receivable when they are deemed uncollectible, and payments subsequently received on such receivables are credited to the allowance for credit losses.
Inventories	Inventories Inventories include raw stockpiles, in-process product and finished product available for shipment, as well as spare parts and supplies for routine facility maintenance. We value inventory at the lower of cost and net realizable value. Cost is determined using the first-in, first-out and average cost methods. Our inventoriable costs include production costs and transportation and additional service costs as applicable.
Property, Plant and Mine Development	Property, Plant and Mine Development Plant and equipment Plant and equipment is recorded at cost and depreciated over their estimated useful lives. Interest incurred during construction of facilities is capitalized and depreciated over the life of the asset. Costs for normal repairs and maintenance that do not extend economic life or improve service potential are expensed as incurred. Costs of improvements that extend economic life or improve service potential are capitalized and depreciated over the estimated remaining useful life. Depreciation is recorded using the straight-line method over the assets’ estimated useful lives as follows: buildings (15 years); land improvements (10 years); machinery and equipment, including computer equipment and software (3-10 years); furniture and fixtures (8 years). Leasehold improvements are depreciated over the shorter of the asset life or lease term. Construction-in-progress is primarily comprised of machinery and equipment which have not yet been placed in service. Mining property and development Mining property and development includes mineral deposits and mine exploration and development. Mineral deposits are initially recognized at cost, which approximates the estimated fair value on the date of purchase. Mine exploration and development costs include engineering and mineral studies, drilling and other related costs to delineate an ore body, and the removal of overburden to initially expose an ore body for production. Costs incurred before mineralization are classified as proven and probable reserves are expensed and classified as exploration or advanced projects, research and development expense. Capitalization of mine development project costs, which meet the definition of an asset, begins once mineralization is classified as proven and probable reserves. The cost of removing overburden and waste materials to access the ore body at an open pit mine prior to the production phase are referred to as “pre-stripping costs.” Pre-stripping costs are capitalized during the development of an open pit mine. The production phase of an open pit mine commences when saleable minerals, beyond a de minimis amount, are produced. Stripping costs incurred during the production phase of a mine are variable production costs that are included as a component of inventory to be recognized in costs applicable to sales in the same period as the revenue from the sale of inventory. Depletion and amortization of mineral deposits and mine development costs are recorded as the minerals are extracted, based on units of production and engineering estimates of mineable reserves. The impact of revisions to reserve estimates is recognized on a prospective basis. See Note G - Property, Plant and Mine Development. Mine reclamation costs and asset retirement obligations We recognize the fair value of any liability for conditional asset retirement obligations, if sufficient information exists to reasonably estimate the fair value of the liability. These obligations include environmental remediation liabilities when incurred, which is generally upon acquisition, construction or development and/or through the normal operation of the asset. These obligations also generally include the estimated net future costs of dismantling, restoring and reclaiming operating mines and related mine sites in accordance with federal, state, local regulatory and land lease agreement requirements. The liability is accreted over time through periodic charges to earnings. In addition, the asset retirement cost is capitalized as part of the asset’s carrying value and amortized over the life of the related asset. Reclamation costs are periodically adjusted to reflect changes in the estimated present value resulting from the passage of time and revisions to the estimates of either the timing or amount of the reclamation and abandonment costs. The reclamation obligation is based on when spending for an existing environmental disturbance will occur. If the asset retirement obligation is settled for other than the carrying amount of the liability, a gain or loss is recognized on settlement. We review, on an annual basis, unless otherwise deemed necessary, the reclamation obligation at each mine site in accordance with ASC guidance for accounting for reclamation obligations.
Impairment or Disposal of Property, Plant and Mine Development	Impairment or Disposal of Property, Plant and Mine Development We periodically evaluate whether current events or circumstances indicate that the carrying value of our property, plant and equipment assets may not be recoverable. If circumstances indicate that the carrying value may not be recoverable, we estimate future undiscounted net cash flows using estimates of proven and probable sand reserves, estimated future sales prices (considering historical and current prices, price trends and related factors) and operating costs and anticipated capital expenditures. If the undiscounted cash flows are less than the carrying value of the assets, we recognize an impairment loss equal to the amount by which the carrying value exceeds the fair value of the assets. The recoverability of the carrying value of our mineral properties is dependent upon the successful development, start-up and commercial production of our mineral deposit and the related processing facilities. Our evaluation of mineral properties for potential impairment primarily includes assessing the existence or availability of required permits and evaluating changes in our mineral reserves, or the underlying estimates and assumptions, including estimated production costs. Assessing the economic feasibility requires certain estimates including the prices of products to be produced and processing recovery rates, as well as operating and capital costs. Gains on the sale of property, plant and mine development are included in income when the assets are disposed of provided there is more than reasonable certainty of the collectability of the sales price and any future activities required to be performed by us relating to the disposal of the assets are complete or insignificant. Upon retirement or disposal of assets, all costs and related accumulated depreciation or amortization are written-off.
Goodwill and Other Intangible Assets and Related Impairment	Goodwill and Other Intangible Assets and Related Impairment Our intangible assets consist of goodwill, which is not amortized, indefinite-lived intangibles, which consist of certain trade names that are not subject to amortization, intellectual property and customer relationships. Intellectual property mainly consists of patents and technology, and it is amortized on a straight-line basis over an average useful life of 15 years. Customer relationships are amortized on a straight-line basis over their useful life of 13 - 20 years. Intangible assets that are amortized are reviewed for impairment annually, or more frequently when indicators of impairment exist. Goodwill represents the excess of the purchase price of business combinations over the fair value of net assets acquired. Goodwill and trade names are reviewed for impairment annually as of October 31, or more frequently when indicators of impairment exist. An impairment exists if the fair value of a reporting unit to which goodwill has been allocated, or the fair value of indefinite-lived intangible assets, is less than their respective carrying values. Prior to conducting a formal impairment test, we have an option to assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that is more likely than not (more than 50%) that the fair value of a reporting unit is less than its carrying amount. Such qualitative factors may include the following: macroeconomic conditions; industry and market considerations; cost factors; overall financial performance; and other relevant entity-specific events. If the qualitative assessment determines that an impairment is more likely than not, or if we choose to bypass the qualitative assessment, we perform a quantitative assessment by comparing the fair value of a reporting unit with its carrying amount and recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. A trade name is a legally protected trade or similar mark. Acquired trade names are valued using an income method approach, generally the relief-from-royalty valuation method. The method uses a royalty rate based on comparable marketplace royalty agreements for similar types of trade names and applies it to the after-tax discounted free cash flow attributed to the trade name. The discount rate used is based on an estimated weighted average cost of capital and the anticipated risk for intangible assets. The valued trade names have an indefinite life based on our plans and expectations for the trade names going forward and are reviewed for impairment annually, or more frequently when indicators of impairment exist. Intellectual property and technology (“IP”) is a design, work or invention that is the result of creativity to which one has ownership rights that may be protected through a patent, copyright, trademark or service mark. IP is valued using the relief-from-royalty valuation method. The method uses a royalty rate based on comparable marketplace royalty agreements for similar types of IP and applies it to the after-tax discounted free cash flow attributed to the IP. The discount rate used is based on an estimated weighted average cost of capital and the anticipated risk for intangible assets. The IP is amortized following the pattern in which the expected benefits will be consumed or otherwise used up over each component’s useful life, based on our plans and expectations for the IP going forward, which is generally the underlying IP’s legal expiration dates. IP is reviewed for impairment annually, or more frequently when indicators of impairment exist. Customer relationships are intangible assets that consist of historical and factual information about customers and contacts collected from repeat transactions with customers, with or without any underlying contracts. The information is generally organized as customer lists or customer databases. We have the expectation of repeat patronage from these customers based on the customers’ historical purchase activity, which creates the intrinsic value over a finite period of time and translates into the expectation of future revenue, income, and cash flow. Customer relationships are valued using projected operating income, adjusted for estimated future existing customer growth less estimated future customer attrition, net of charges for net tangible assets, IP charge, trade name charge and work force. The concluded value is the after-tax discounted free cash flow. Customer relationships are reviewed for impairment annually, or more frequently when indicators of impairment exist.
Leases	Leases We lease railroad cars, office space, mining property, mining/processing equipment, and transportation and other equipment. Operating leases are included in lease right-of-use (“ROU”) assets, current portion of operating lease liabilities, and operating lease liabilities in our consolidated balance sheets. Finance leases are included in lease right-of-use assets, current portion of long-term debt, and long-term debt in our consolidated balance sheets. Leases with an initial term of 12 months or less are not recorded on the balance sheet. ROU assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. ROU assets and liabilities are recognized at the commencement date of the lease based on the present value of lease payments over the lease term. As most of our leases do not provide an implicit rate, we use our incremental borrowing rate based on the information available at the commencement date in determining the present value of lease payments. The ROU assets also include any lease payments made at or before the commencement date of the lease and excludes lease incentives. Our lease terms may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Lease expense for lease payments is recognized on a straight-line basis over the lease term. We have lease agreements with lease and non-lease components, the latter of which are generally accounted for separately. See Note Q - Leases. We periodically evaluate whether current events or circumstances indicate that the carrying value of our ROU assets exceeds fair value. If circumstances indicate an impairment exists, we estimate fair value primarily utilizing internally developed cash flow models and quoted market prices, discounted at an appropriate weighted average cost of capital. If the undiscounted cash flows are less than the carrying value of the assets, we recognize an impairment loss equal to the amount by which the carrying value exceeds the fair value of the assets.
Revenue Recognition and Deferred Revenues	Revenue Recognition Products We derive our product sales by mining and processing minerals that our customers purchase for various uses. Our product sales are primarily a function of the price per ton and the number of tons sold. We primarily sell our products through individual purchase orders executed under short-term price agreements or at prevailing market rates. The amount invoiced reflects product, transportation and additional handling services as applicable, such as storage, transloading the product from railcars to trucks and last mile logistics to the customer site. We invoice most of our product customers on a per shipment basis, although for some larger customers, we consolidate invoices weekly or monthly. Standard collection terms are net 30 days, although extended terms are offered in competitive situations. We recognize revenue for products and materials at a point in time following the transfer of control of such items to the customer, which typically occurs upon shipment or delivery depending on the terms of the underlying contracts. We account for shipping and handling activities related to product and material sales contracts with customers as costs to fulfill our promise to transfer the associated products pursuant to the accounting policy election allowed under ASC 606-10-25-18b. Accordingly, we record amounts billed for shipping and handling costs as a component of net sales and accrue and classify related costs as a component of cost of sales at the time revenue is recognized. For a limited number of customers, we sell under long-term, minimum purchase supply agreements. These agreements define, among other commitments, the volume of product that our customers must purchase, the volume of product that we must provide and the price that we will charge and that our customers will pay for each product. Prices under these agreements are generally fixed and subject to certain contractual adjustments. Sometimes these agreements may undergo negotiations regarding pricing and volume requirements, which may often occur in volatile market conditions. While these negotiations continue, we may deliver product at prices or at volumes below the requirements in our existing supply agreements. An executed order specifying the type and quantity of product to be delivered, in combination with the noted agreements, comprise our contracts in these arrangements. Service We derive our service revenues primarily through the provision of transportation, equipment rental, and contract labor services to companies in the oil and gas industry. Transportation services typically consist of transporting customer proppant from storage facilities to proximal well-sites and are contracted through work orders executed under established pricing agreements. The amount invoiced reflects the transportation services rendered. Equipment rental services provide customers with use of either dedicated or nonspecific wellhead proppant delivery equipment solutions for contractual periods defined either through formal lease agreements or executed work orders under established pricing agreements. The amounts invoiced reflect the length of time the equipment set was utilized in the billing period. Contract labor services provide customers with proppant delivery equipment operators through work orders executed under established pricing agreements. The amounts invoiced reflect the amount of time our labor services were utilized in the billing period. We typically invoice our customers on a weekly or monthly basis; however, some customers receive invoices upon well-site operation completion. Standard collection terms are net 30 days, although extended terms are offered in competitive situations. We typically recognize revenue for specific, dedicated equipment set rental arrangements under ASC 842, Leases. For the remaining components of service revenue, we have applied the practical expedient allowed under ASC 606-10-55-18 to recognize transportation revenues in proportion to the amount we have the right to invoice. Contracts with Multiple Performance Obligations From time to time, we may enter into contracts that contain multiple performance obligations, such as work orders containing a combination of product, transportation, equipment rentals, and contract labor services. For these arrangements, we allocate the transaction price to each performance obligation identified in the contract based on relative standalone selling prices, or estimates of such prices, and recognize the related revenue as control of each individual product or service is transferred to the customer, in satisfaction of the corresponding performance obligations. We typically invoice our customers on a weekly or monthly basis; however, some customers received invoices upon well-site operation completion. Standard collection terms are net 30 days, although extended terms are offered in competitive situations. Taxes Collected from Customers and Remitted to Governmental Authorities. We exclude from our measurement of transaction prices all taxes assessed by governmental authorities that are both (i) imposed on and concurrent with a specific revenue-producing transaction and (ii) collected from customers. Accordingly, such tax amounts are not included as a component of net sales or cost of sales. See Note S - Revenue. Deferred Revenues For a limited number of customers, we enter into supply agreements which give customers the right to make advanced payments toward the purchase of certain products at specified volumes over an average initial period of one to fifteen years. These payments represent consideration that is unconditional and for which we have yet to transfer the related product. These payments are recorded as contract liabilities referred to as “deferred revenues” upon receipt and recognized as revenue upon delivery of the related product.
Unbilled Receivables	Unbilled Receivables Revenues recognized in advance of invoice issuance create assets referred to as “unbilled receivables.” Any portion of our unbilled receivables for which our right to consideration is conditional on a factor other than the passage of time is considered a contract asset. These assets are presented on a combined basis with accounts receivable and are converted to accounts receivable once billed.
Debt Issuance Costs	Debt Issuance Costs We defer costs directly associated with acquiring third-party financing, primarily loan origination costs and related professional expenses. Debt issuance costs are deferred and amortized using the effective interest rate method over the term of our senior secured Term Loan facility and the straight-line method for our Revolver facility. Debt issuance costs related to long-term debt are reflected as a direct deduction from the carrying amount of the debt.
Employee Benefit Plans	Employee Benefit Plans We provide a range of benefits to our employees and retired employees, including pensions and post-retirement healthcare and life insurance benefits. We record annual amounts relating to these plans based on calculations specified by generally accepted accounting principles, which include various actuarial assumptions, including discount rates, assumed rates of returns, compensation increases, turnover rates, mortality tables, and healthcare cost trend rates. We review the actuarial assumptions on an annual basis and make modifications to the assumptions based on current rates and trends when it is deemed appropriate to do so. As required by U.S. generally accepted accounting principles, the effect of the modifications is generally recorded or amortized over future periods. We believe that the assumptions utilized in recording our obligations under the plans are reasonable based on advice from our actuaries and information as to assumptions used by other employers.
Environmental Costs	Environmental Costs Environmental costs, other than qualifying capital expenditures, are accrued at the time the exposure becomes known and costs can be reasonably estimated. Costs are accrued based upon management’s estimates of all direct costs, after taking into account expected reimbursement by third parties (primarily the sellers of acquired businesses) and are reviewed by outside consultants. Environmental costs are charged to expense unless a settlement with an indemnifying party has been reached.
Self-Insurance	Self-Insurance We are self-insured for various levels of employee health insurance coverage, workers’ compensation and third-party product liability claims alleging occupational disease. We purchase insurance coverage for claim amounts which exceed our self-insured retentions. Depending on the type of insurance, these self-insured retentions range from $0.1 million to $0.5 million per occurrence. Our insurance reserves are accrued based on estimates of the ultimate cost of claims expected to occur during the covered period. These estimates are prepared with the assistance of outside actuaries and consultants. Our actuaries periodically review the volume and amount of claims activity, and based upon their findings, we adjust our insurance reserves accordingly. The ultimate cost of claims for a covered period may differ from our original estimates. The current portion of our self-insurance reserves is included in accrued liabilities and the non-current portion is included in other long-term obligations in our Balance Sheets.
Research and Development Costs	Research and Development Costs We may incur immaterial internal research and development (“R&D”) expenditures, and research and development conducted for others, all of which are expensed as incurred, and included in selling, general and administrative expense. R&D costs may include, but are not limited to, research and administrative salaries, contractor fees, building costs, utilities, administrative expenses, and allocations of corporate costs.
Advertising Costs	Advertising Costs We recognize advertising expense when incurred as selling, general and administrative expense.
Equity-based Compensation	Equity-based Compensation We grant stock options, restricted stock, restricted stock units and performance share units to certain of our employees and directors under the Amended and Restated U.S. Silica Holdings, Inc. 2011 Incentive Compensation Plan. We recognize the cost of employee services rendered in exchange for awards of equity instruments. Vesting of restricted stock and restricted stock units is based on the individual continuing to render service over a pre-defined vesting schedule, generally three years. Cash dividend equivalents are accrued and paid to the holders of time-based restricted stock units and restricted stock. The fair value of the restricted stock awards is equal to the market price of our stock at date of grant. The restricted award-related compensation expense is recognized on a straight-line basis over the vesting period. We grant performance share units to certain employees in which the number of shares of common stock ultimately received is determined based on achievement of certain performance thresholds over a specified performance period (generally three years) in accordance with the stock award agreement. Cash dividend equivalents are not accrued or paid on performance share units. We recognize expense based on the estimated vesting of our performance share units granted and the grant date market price. The estimated vesting of the performance share units is principally based on the probability of achieving certain financial performance levels during the vesting periods. In the period it becomes probable that the minimum performance criteria specified in the award agreement will be achieved, we recognize expense for the proportionate share of the total fair value of the award related to the vesting period that has already lapsed. The remaining fair value of the award is expensed on a straight-line basis over the remaining vesting period. We grant certain employees performance share units, the vesting of which is based on our total shareholder return (“TSR”) ranking among a peer group over a three-year period. The number of units that will vest will depend on the percentage ranking of our TSR compared to the TSRs for each of the companies in the peer group over the performance period. For these awards subject to market conditions, a binomial-lattice model (i.e., Monte Carlo simulation model) is used to fair value these awards at grant date. We also grant certain employees performance share units, the vesting of which is based on adjusted free cash flow ("ACF") targets. The number of ACF measured units that will vest will be based on ACF achievement versus target. The ACF targets are set annually and are approved by the Board of Directors. The related compensation expense is recognized on a straight-line basis over the vesting period.
Income Taxes	Income Taxes Deferred taxes are recognized on the liability method whereby deferred tax assets are recognized for deductible temporary differences and operating loss and tax credit carry forwards and deferred tax liabilities are recognized for taxable temporary differences. This approach requires recognition of deferred tax liabilities and assets for the expected future tax consequences of events that have been included in the financial statements or tax returns. Under this method, deferred tax liabilities and assets are determined based upon the difference between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the expenses are expected to reverse. Valuation allowances are provided if, based on the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. We recognize a tax benefit associated with an uncertain tax position when, in management’s judgment, it is more likely than not that the position will be sustained upon examination by a taxing authority. For a tax position that meets the more likely than not recognition threshold, we initially and subsequently measure the tax benefit as the largest amount that we judge to have a greater than 50% likelihood of being realized upon ultimate settlement with a taxing authority. The liability associated with unrecognized tax benefits is adjusted periodically due to changing circumstances, such as the progress of tax audits, case law developments and new or emerging legislation. Such adjustments are recognized entirely in the period in which they are identified. The effective tax rate includes the net impact of changes in the liability for unrecognized tax benefits and subsequent adjustments as considered appropriate by management.
Financial Instruments	Financial Instruments We currently use natural gas swaps to manage our exposure to natural gas price increases. Our policy is to not hold or issue derivative financial instruments for trading or speculative purposes. Gains and losses on derivatives designated as cash flow hedges are recorded in other comprehensive income (loss), net of tax, and reclassified to earnings in a manner that matches the timing of the earnings impact of the hedged transactions. The ineffective portion of all hedges, if any, is recognized currently in income.
Foreign Currency Translation	Foreign Currency Translation For our operations in countries where the functional currency is other than the U.S. dollar, balance sheet amounts are translated using the exchange rate in effect at the balance sheet date. Income statement amounts are translated monthly using the average exchange rate for the respective month. The gains and losses resulting from the changes in exchange rates from year-to-year are recorded as a component of accumulated other comprehensive income or loss as currency translation adjustments, net of tax. Any gains or losses on transactions in currencies other than the functional currency are included in other income (expense), net, including interest income.
Comprehensive Income (Loss)	Comprehensive Income (loss) In addition to net income (loss), comprehensive income (loss) includes all changes in equity during a period, such as adjustments to minimum pension liabilities and the effective portion of changes in fair value of derivative instruments that qualify as cash flow hedges.
Business Combinations	Business Combinations We account for business combinations using the acquisition method of accounting. Under this method, acquired assets, including separately identifiable intangible assets and any assumed liabilities, are recorded at their acquisition date estimated fair value. The excess of purchase price over the fair value amounts assigned to the assets acquired and liabilities assumed represents the goodwill amount resulting from the acquisition. Determining the fair value of assets acquired and liabilities assumed involves the use of significant estimates and assumptions.
New Accounting Pronouncements Recently Adopted and New Accounting Pronouncements Not Yet Adopted	New Accounting Pronouncements Recently Adopted In March 2020, the FASB issued Accounting Standards Update ("ASU") 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting followed by ASU 2021-01, Reference Rate Reform (Topic 848): Scope, issued in January 2021 to provide clarifying guidance regarding the scope of Topic 848. ASU 2020-04 was issued to provide optional guidance for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting. Generally, the guidance is to be applied as of any date from the beginning of an interim period that includes or is subsequent to March 12, 2020, or prospectively from a date within an interim period that includes or is subsequent to March 12, 2020, up to the date that the financial statements are available to be issued. ASU 2020-04 and ASU 2021-01 are effective for all entities through December 31, 2022. In April 2022, the FASB proposed to extend the effective date through December 31, 2024 and affirmed this decision in December 2022. Upon execution of the Fourth Amended and Restated Credit Agreement, we have transitioned from LIBOR. See Note J - Debt for discussion of the Fourth Amended and Restated Credit Agreement. New Accounting Pronouncements Not Yet Adopted In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. The amendments in this Update improve financial reporting by requiring disclosure of incremental segment information on an annual and interim basis for all public entities to enable investors to develop more decision-useful financial analyses. The amendments in this Update do not change or remove current disclosure requirements as required by Topic 280. The amendments in this Update also do not change how a public entity identifies its operating segments, aggregates those operating segments, or applies the quantitative thresholds to determine its reportable segments. The amendments in this Update are effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Public entities will be required to apply the amendments in this Update retrospectively to all prior periods presented in the financial statements. We are currently evaluating the effect this guidance will have on our disclosures. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. The amendments in this Update related to the rate reconciliation and income taxes paid disclosures improve the transparency of income tax disclosures by requiring (1) consistent categories and greater disaggregation of information in the rate reconciliation and (2) income taxes paid disaggregated by jurisdiction. The amendments allow investors to better assess, in their capital allocation decisions, how an entity’s worldwide operations and related tax risks and tax planning and operational opportunities affect its income tax rate and prospects for future cash flows. The other amendments in this Update improve the effectiveness and comparability of disclosures by (1) adding disclosures of pretax income (or loss) and income tax expense (or benefit) to be consistent with U.S. Securities and Exchange Commission (SEC) Regulation S-X 210.4-08(h), Rules of General Application—General Notes to Financial Statements: Income Tax Expense, and (2) removing disclosures that no longer are considered cost beneficial or relevant. The amendments in this Update are effective for annual periods beginning after December 15, 2024. We are currently evaluating the effect this guidance will have on our disclosures.
Fair Value Measurement	Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Fair value is estimated by applying the following hierarchy, which prioritizes the inputs used to measure fair value into three levels and bases the categorization within the hierarchy upon the lowest level of input that is available and significant to the fair value measurement: Level 1—Quoted prices in active markets for identical assets or liabilities. Level 2—Observable inputs other than quoted prices in active markets for identical assets and liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3—Inputs that are generally unobservable and typically reflect management’s estimate of assumptions that market participants would use in pricing the asset or liability. Cash Equivalents Due to the short-term maturity, we believe our cash equivalent instruments at December 31, 2023 and 2022, approximate their reported carrying values, therefore, we have classified our cash equivalents as Level 1 of the fair value hierarchy. Long-Term Debt, Including Current Maturities We believe that the fair values of our long-term debt, including current maturities, approximate their carrying values based on their effective interest rates compared to current market rates, therefore we have classified our long-term debt as Level 1 of the fair value hierarchy.
Derivative Instruments	Derivative Instruments The estimated fair value of our derivative instruments is recorded at each reporting period and is determined based on inputs that are readily available in public markets or can be derived from information available in publicly quoted markets. Therefore, we have classified these swap agreements as Level 2 of the fair value hierarchy.

Equity-Based Compensation - Stock Options Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Number of Shares
Outstanding balance at the beginning (in shares)	508,523
Granted (in shares)	0	0	0
Exercised (in shares)	0	(90,000)	(10,164)
Forfeited (in shares)	(122,009)
Expired (in shares)	(37,434)
Outstanding balance at the end (in shares)	349,080	508,523
Exercisable (in shares)	349,080
Weighted Average Exercise Price
Outstanding balance at the beginning (in dollars per share)	$ 36.22
Granted (in dollars per share)	0
Exercised (in dollars per share)	0
Forfeited (in dollars per share)	36.79
Expired (in dollars per share)	24.80
Outstanding balance at the end (in dollars per share)	37.24	$ 36.22
Exercisable (in dollars per share)	$ 37.24
Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2022	$ 0
Exercised	0	$ 613	$ 44
Outstanding at December 31, 2023	0	$ 0
Exercisable at December 31, 2023	$ 0
Weighted Average Remaining Contractual Term in Years
Outstanding at the beginning, Weighted Average Remaining Contractual Term in Years	1 year 1 month 6 days	2 years
Outstanding at the end, Weighted Average Remaining Contractual Term in Years	1 year 1 month 6 days	2 years
Exercisable, Weighted Average Remaining Contractual Term in Years	1 year 1 month 6 days

Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance as of January 1	$ 856	$ 856	$ 0
Additions for tax positions of prior years	0	0	856
Lapse in statute of limitations	(856)	0	0
Balance as of December 31	$ 0	$ 856	$ 856

Revenue - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
Revenue - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Assets	$ 2,096,593	$ 2,214,580
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Disaggregation of Revenue [Line Items]
Remaining duration period of expected satisfaction of performance obligations	1 year
Foreign Operations
Disaggregation of Revenue [Line Items]
Assets	$ 23,100	$ 33,400
Minimum \| Supply Agreement
Disaggregation of Revenue [Line Items]
Deferred revenue, average initial contract term	1 year
Maximum \| Supply Agreement
Disaggregation of Revenue [Line Items]
Deferred revenue, average initial contract term	15 years

- Definition

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 810
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (bb)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481203/810-10-50-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 810
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 25
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481231/810-10-45-25

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 323
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481687/323-10-50-3

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 28
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-28

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Topic 852
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481372/852-10-55-10

Reference 7: http://www.xbrl.org/2003/role/exampleRef
-Topic 946
-SubTopic 830
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480167/946-830-55-12

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+ Details

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References + Details

Accounts Payable and Accrued Liabilities

12 Months Ended

Dec. 31, 2023

Payables and Accruals [Abstract]

ACCOUNTS PAYABLE AND ACCRUED LIABILITIES

NOTE I—ACCOUNTS PAYABLE AND ACCRUED LIABILITIES

Accounts payable and accrued liabilities (in thousands) consisted of the following:


	December 31,
	2023		2022
Trade payables	$	123,667	$	182,555
Accrued salaries and wages	7,013		10,911
Accrued vacation liability	3,567		3,093
Current portion of liability for pension and post-retirement benefits	986		1,118
Accrued healthcare liability	1,571		1,492
Accrued property taxes and sales taxes	3,422		4,287

Current portion of derivative liability	1,819		2,312
Other accrued liabilities	5,434		10,471
Accounts payable and accrued liabilities	$	147,479	$	216,239

Other accrued liabilities consist of employer related expenses, royalties payable, accrued interest payable, and other items.

Income Taxes

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

INCOME TAXES

NOTE R— INCOME TAXES

We evaluate our deferred tax assets periodically to determine if valuation allowances are required. Ultimately, the realization of deferred tax assets is dependent upon generation of future taxable income during those periods in which temporary differences become deductible and/or credits can be utilized. To this end, management considers the level of historical taxable income, the scheduled reversal of deferred tax liabilities, tax-planning strategies and projected future taxable income. Based on these considerations, and the carry-forward availability of a portion of the deferred tax assets, management believes it is more likely than not that we will realize the benefit of the deferred tax assets.

Income (loss) before income taxes (in thousands) consisted of the following:


	Year ended December 31,
	2023		2022		2021
United States	$	172,214	$	87,686	$	(48,328)
Foreign	23,355		16,313		11,252
Total	$	195,569	$	103,999	$	(37,076)

Income tax (expense) benefit (in thousands) consisted of the following:


	Year ended December 31,
	2023		2022		2021
Current:
Federal	$	(6,603)	$	(1,650)	$	—
State	(5,936)		(3,078)		(3,353)
Foreign	(1,230)		(491)		(1,385)
	(13,769)		(5,219)		(4,738)
Deferred:
Federal	(32,972)		(17,881)		7,589
State	(2,339)		(3,059)		(96)
Foreign	—		—		—
	(35,311)		(20,940)		7,493
Income tax (expense) benefit	$	(49,080)	$	(26,159)	$	2,755

Income tax (expense) benefit (in thousands) differed from the amount that would be provided by applying the U.S. federal statutory rate due to the following:


	Year ended December 31,
	2023		2022		2021
Income tax (expense) benefit computed at U.S. federal statutory rate	$	(41,069)	$	(21,838)	$	7,786
Decrease (increase) resulting from:
Statutory depletion	3,758		2,963		2,012

Prior year tax return reconciliation	(996)		(1,564)		(2,490)
State income taxes, net of federal benefit	(7,385)		(4,003)		445
Impact of international operations	(854)		(830)		(380)
Unrecognized tax benefits	1,055		(89)		(1,302)

Equity compensation	1,684		(195)		(627)
Executive compensation	(4,963)		(300)		(2,092)
Other, net	(310)		(303)		(597)
Income tax (expense) benefit	$	(49,080)	$	(26,159)	$	2,755

Deferred tax assets and liabilities are recognized for the estimated future tax effects, based on enacted tax laws, of temporary differences between the values of assets and liabilities recorded for financial reporting and for tax purposes and of net operating loss and other carryforwards.

The tax effects of the types of temporary differences and carry forwards that gave rise to deferred tax assets and liabilities (in thousands) consisted of the following:


	December 31,
	2023		2022
Gross deferred tax assets:
Net operating loss carry forward and state tax credits	$	23,839	$	54,638
Pension and post-retirement benefit costs	6,214		6,789

Property, plant and equipment	8,210		5,935
Accrued expenses	12,989		18,232
Inventories	369		—
Federal tax credits	—		1,047
Stock-based compensation expense	4,187		6,374
Interest expense limitation	21,685		19,826
Intangibles	4,139		6,366
Lease obligation liability	8,918		11,393
Other	7,406		5,886
Total deferred tax assets	97,956		136,486
Gross deferred tax liabilities:
Land and mineral property basis difference	(130,764)		(124,669)
Fixed assets and depreciation	(67,014)		(74,714)
Inventories	—		(1,170)

Other	(636)		(569)
Total deferred tax liabilities	(198,414)		(201,122)
Net deferred tax liabilities	$	(100,458)	$	(64,636)

We have federal net operating loss carry forwards of approximately $74.6 million at December 31, 2023, of which $50.5 million is subject to the 80% taxable income limitation with no expiration. The remaining portion of those losses are subject to an annual limitation under Internal Revenue Code Section 382, which will begin to expire 2028 through 2033, but are expected to be fully realized.

The following table is a reconciliation of our unrecognized tax benefits (in thousands):


	Year ended December 31,
	2023		2022		2021
Balance as of January 1	$	856	$	856	$	—
Additions for tax positions of prior years	—		—		856
Lapse in statute of limitations	(856)		—		—
Balance as of December 31	$	—	$	856	$	856

We include potential interest and penalties related to uncertain tax positions in the income tax (expense)/benefit line item in our Consolidated Statements of Operations. During 2023, 2022 and 2021, we accrued estimated interest and penalties related to uncertain tax positions of approximately zero, $0.1 million and $0.4 million, respectively. As of December 31, 2023, 2022 and 2021, we had approximately zero, $0.5 million, and $0.4 million, respectively, of interest and penalties related to uncertain tax positions. We do not expect a significant change to the unrecognized tax benefits during the next twelve months. Tax returns filed with the IRS for the years 2020 through 2022 along with tax returns filed with numerous state entities remain subject to examination.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-Name Accounting Standards Codification
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-URI https://asc.fasb.org//740/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
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-Name Accounting Standards Codification
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-Paragraph 14
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-URI https://asc.fasb.org//1943274/2147482685/740-10-50-14

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
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-Paragraph 21
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-URI https://asc.fasb.org//1943274/2147482685/740-10-50-21

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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-Topic 740
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482603/740-30-50-2

+ Details

Related Party Transactions (Details) - USD ($)	12 Months Ended
Related Party Transactions (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Related Party Transactions [Abstract]
Related party transaction, amounts of transaction	$ 0	$ 0	$ 0

Pension and Post-Retirement Benefits - Net Pension Benefit Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension Plans, Postretirement and Other Employee Benefits
Defined Benefit Plan Net Periodic Benefit Cost Credit Settlement And Curtailment Gain Loss Statement Of Income Or Comprehensive Income Extensible List Not Disclosed Flag	Settlement loss
Settlement loss	$ 1,803	$ 0	$ 0
Pension Benefits
Pension Plans, Postretirement and Other Employee Benefits
Service cost	2,325	2,516	2,855
Interest cost	5,343	3,120	2,619
Expected return on plan assets	(6,373)	(5,887)	(5,688)
Net amortization and deferral	41	2,249	3,212
Net pension benefit or post-retirement costs	3,139	1,998	2,998
Post-retirement Benefits
Pension Plans, Postretirement and Other Employee Benefits
Service cost	8	18	24
Interest cost	332	180	141
Unrecognized prior service cost	(2,063)	0	0
Unrecognized net gain	(792)	(2,360)	(2,204)
Net pension benefit or post-retirement costs	$ (2,515)	$ (2,162)	$ (2,039)

Goodwill and Intangible Assets - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill and intangible asset impairment	$ 0	$ 0
Amortization expense	$ 9,700,000	$ 9,700,000	$ 9,700,000
Technology and intellectual property
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful live of finite-lived intangible assets	15 years
Minimum \| Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful live of finite-lived intangible assets	13 years
Maximum \| Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful live of finite-lived intangible assets	20 years

Equity-Based Compensation

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

EQUITY-BASED COMPENSATION

NOTE N—EQUITY-BASED COMPENSATION

In July 2011, we adopted the U.S. Silica Holdings, Inc. 2011 Incentive Compensation Plan (the “2011 Plan”), which was amended and restated in May 2015, amended and restated effective February 1, 2020, amended and restated effective May 13, 2021, amended and restated effective May 12, 2022 and amended and restated May 11, 2023. The 2011 Plan provides for grants of stock options, restricted stock, performance share units and other incentive-based awards. We believe our 2011 Plan aligns the interests of our employees and directors with those of our common stockholders. At December 31, 2023, we had 4,490,066 shares of common stock that may be issued under the 2011 Plan. We use a combination of treasury stock and new shares if necessary to satisfy option exercises or vesting of restricted awards and performance share units.

Stock Options

The following table summarizes the status of, and changes in, our stock option awards:


	Number of Shares	Weighted Average Exercise Price		Aggregate Intrinsic Value		Weighted Average Remaining Contractual Term in Years
Outstanding at December 31, 2022	508,523	$	36.22	$	—	2.0 years
Granted	—	$	—	$	—
Exercised	—	$	—	$	—
Forfeited	(122,009)	$	36.79	$	—
Expired	(37,434)	$	24.80	$	—
Outstanding at December 31, 2023	349,080	$	37.24	$	—	1.1 years
Exercisable at December 31, 2023	349,080	$	37.24	$	—	1.1 years

There were no grants of stock options during the years ended December 31, 2023, 2022 and 2021.

The following table summarizes stock option exercise activity:


	As of December 31,
	2023		2022		2021
Options exercised (in actual shares)	—		90,000		10,164
Intrinsic value of options exercised (in thousands)	$	—	$	613	$	44
Cash received from options exercised (in thousands)	$	—	$	955	$	105
Tax benefit realized from options exercised (in thousands)	$	—	$	148	$	11

As of December 31, 2023, 2022 and 2021, there was no unrecognized compensation expense related to these options. We account for forfeitures as they occur.

Restricted Stock and Restricted Stock Unit Awards

The following table summarizes the status of, and changes in, our unvested restricted stock awards:


	Number of Shares	Grant Date Weighted Average Fair Value
Unvested, December 31, 2022	1,438,386	$	9.37
Granted	776,339	$	12.16
Vested	(792,727)	$	9.00
Forfeited	(168,019)	$	9.41
Unvested, December 31, 2023	1,253,979	$	11.33

We granted 776,339, 728,357 and 881,261 restricted stock and restricted stock unit awards during the years ended December 31, 2023, 2022 and 2021, respectively. The fair value of the awards was based on the market price of our stock at date of grant.

We recognized $7.6 million, $6.8 million and $7.3 million of equity-based compensation expense related to restricted stock awards during the years ended December 31, 2023, 2022 and 2021, respectively. As of December 31, 2023, there was $8.4 million of unrecognized compensation expense related to these restricted stock awards, which is expected to be recognized over a weighted-average period of 1.8 years.

We also granted cash awards during the year ended December 31, 2020. These awards vested over a period of three years and were settled in cash. As such, these awards were classified as liability instruments. We recognized zero, $0.9 million and $0.9 million of expense related to these awards for the years ended December 31, 2023, 2022 and 2021. The liability for these awards was included in accounts payable and other accrued liabilities on our balance sheets. These awards were remeasured at fair value each reporting period with resulting changes reflected in our income statements. As of December 31, 2023, there was no unrecognized expense related to these awards.

Performance Share Unit Awards

The following table summarizes the status of, and changes in, our performance share unit awards:


	Number of Shares	Grant Date Weighted Average Fair Value
Unvested, December 31, 2022	2,292,751	$	9.51
Granted	1,295,904	$	9.54
Vested	(1,549,033)	$	6.60
Forfeited/Cancelled	(165,562)	$	11.76
Unvested, December 31, 2023	1,874,060	$	11.73

We granted 1,295,904, 920,681 and 886,091 of performance share unit awards during the years ended December 31, 2023, 2022 and 2021, respectively. A portion of these awards was measured against total shareholder return ("TSR"), and a portion was measured against adjusted free cash flow ("ACF") targets. The grant date weighted average fair value of these awards was estimated to be $9.54, $11.79 and $12.04 for the years ended December 31, 2023, 2022 and 2021, respectively. The number of TSR measured units that will vest will depend on the percentage ranking of our TSR compared to the TSR for each of the companies in the peer group over the three year period from January 1, 2023 through December 31, 2025 for the 2023 grant, January 1, 2022 through December 31, 2024 for the 2022 grant, and January 1, 2021 through December 31, 2023 for the 2021 grant. The number of ACF measured units that will vest will be based on ACF achievement versus target. The ACF targets are set annually and are approved by the Board of Directors. The related compensation expense is recognized on a straight-line basis over the vesting period.

The grant date fair value for the TSR awards was estimated using a Monte Carlo simulation model. The Monte Carlo simulation model requires the use of highly subjective assumptions. Our key assumptions in the model included the price and the expected volatility of our common stock and our self-determined peer group companies’ stock, risk-free rate of interest, dividend yields and cross-correlations between our common stock and our self-determined peer group companies' stock.

We recognized $7.0 million, $11.5 million and $11.5 million of compensation expense related to performance share unit awards during the years ended December 31, 2023, 2022 and 2021, respectively. As of December 31, 2023, there was $7.8 million of unrecognized compensation expense related to these performance share unit awards, which is expected to be recognized over a weighted-average period of 1.7 years.

We also granted cash awards during the year ended December 31, 2020. These awards vested over a period of three years and were settled in cash. As such, these awards were classified as liability instruments. We recognized $0.1 million, $1.1 million and $0.7 million of expense related to these awards for the years ended December 31, 2023, 2022 and 2021, respectively. The liability for these awards was included in accounts payable and other accrued liabilities on our balance sheets. These awards were remeasured at fair value each reporting period with resulting changes reflected in our income statements. As of December 31, 2023, there was no unrecognized expense related to these awards.

Derivative Instruments - Narrative (Details) - USD ($)	12 Months Ended
Derivative Instruments - Narrative (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Interest rate cap agreement \| Cash Flow Hedges
Derivative [Line Items]
Fair value of derivatives	$ 1,900,000	$ 3,100,000
Interest rate cap agreement \| Accounts payables and accrued liabilities \| Cash Flow Hedges
Derivative [Line Items]
Fair value of derivatives	1,800,000	2,300,000
Interest rate cap agreement \| Other long-term obligations \| Cash Flow Hedges
Derivative [Line Items]
Fair value of derivatives	100,000	$ 800,000
Interest Rate Swap
Derivative [Line Items]
Ineffectiveness of derivatives	$ 0

Property, Plant and Mine Development

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment [Abstract]

PROPERTY, PLANT AND MINE DEVELOPMENT

NOTE G—PROPERTY, PLANT AND MINE DEVELOPMENT

Property, plant and mine development (in thousands) consisted of the following:


	December 31, 2023		December 31, 2022
Mining property and mine development	$	793,582	$	789,601
Asset retirement cost	14,728		8,869
Land	53,100		53,128
Land improvements	87,618		76,456
Buildings	76,691		73,151
Machinery and equipment	1,253,734		1,217,933
Furniture and fixtures	2,841		3,922
Construction-in-progress	54,186		55,696
	2,336,480		2,278,756
Accumulated depletion, depreciation, amortization and impairment charges	(1,211,260)		(1,099,922)
Total property, plant and mine development, net	$	1,125,220	$	1,178,834

Depreciation, depletion, and amortization expense related to property, plant and mine development for the years ended December 31, 2023 and 2022 was $124.9 million and $128.4 million, respectively.

Pension and Post-Retirement Benefits - Investment Categories and Their Relative Percentage of Fair Value to Total Plan Assets (Details)	Dec. 31, 2023	Dec. 31, 2022
Pension Benefits \| Equity securities
Pension Plans, Postretirement and Other Employee Benefits
Percentage of the fair value of the total plan assets	54.10%	54.30%
Pension Benefits \| Debt securities
Pension Plans, Postretirement and Other Employee Benefits
Percentage of the fair value of the total plan assets	43.40%	44.20%
Pension Benefits \| Cash
Pension Plans, Postretirement and Other Employee Benefits
Percentage of the fair value of the total plan assets	2.50%	1.50%
Post-retirement Benefits \| Equity securities
Pension Plans, Postretirement and Other Employee Benefits
Percentage of the fair value of the total plan assets	0.00%	0.00%
Post-retirement Benefits \| Debt securities
Pension Plans, Postretirement and Other Employee Benefits
Percentage of the fair value of the total plan assets	0.00%	0.00%
Post-retirement Benefits \| Cash
Pension Plans, Postretirement and Other Employee Benefits
Percentage of the fair value of the total plan assets	0.00%	0.00%

Goodwill and Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2023

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Changes in the Carrying Amount of Goodwill

The changes in the carrying amount of goodwill (in thousands) by business segment consisted of the following:


	Oil & Gas Proppants Segment		Industrial & Specialty Products Segment		Total
Balance at December 31, 2021	$	—	$	185,649	$	185,649

Impairment losses	—		—		—

Balance at December 31, 2022	—		185,649		185,649

Impairment losses	—		—		—
Balance at December 31, 2023	$	—	$	185,649	$	185,649

Schedule of Changes in the Carrying Amount of Definite-Lived Intangible Assets

The changes in the carrying amount of intangible assets (in thousands) consisted of the following:


	December 31, 2023				December 31, 2022
	Gross Carrying Amount		Accumulated Amortization		Net		Gross Carrying Amount		Accumulated Amortization		Net

Technology and intellectual property	$	71,936	$	(34,894)	$	37,042	$	71,651	$	(29,990)	$	41,661
Customer relationships	66,999		(37,597)		29,402		66,999		(32,791)		34,208
Total definite-lived intangible assets:	$	138,935	$	(72,491)	$	66,444	$	138,650	$	(62,781)	$	75,869
Trade names	64,240		—		64,240		64,240		—		64,240
Other	700		—		700		700		—		700
Total intangible assets:	$	203,875	$	(72,491)	$	131,384	$	203,590	$	(62,781)	$	140,809

Schedule of Changes in the Carrying Amount of Indefinite-Lived Intangible Assets

The changes in the carrying amount of intangible assets (in thousands) consisted of the following:


	December 31, 2023				December 31, 2022
	Gross Carrying Amount		Accumulated Amortization		Net		Gross Carrying Amount		Accumulated Amortization		Net

Technology and intellectual property	$	71,936	$	(34,894)	$	37,042	$	71,651	$	(29,990)	$	41,661
Customer relationships	66,999		(37,597)		29,402		66,999		(32,791)		34,208
Total definite-lived intangible assets:	$	138,935	$	(72,491)	$	66,444	$	138,650	$	(62,781)	$	75,869
Trade names	64,240		—		64,240		64,240		—		64,240
Other	700		—		700		700		—		700
Total intangible assets:	$	203,875	$	(72,491)	$	131,384	$	203,590	$	(62,781)	$	140,809

Schedule of Estimated Amortization Expense Related to Definite-Lived Intangible Assets

At December 31, 2023, the estimated amortization expense related to definite-lived intangible assets (in thousands) for the five succeeding years is as follows:


2024	$	9,717
2025	$	9,716
2026	$	9,716
2027	$	9,716
2028	$	9,676

- Definition

Tabular disclosure of goodwill by reportable segment and in total which includes a rollforward schedule.

+ References

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+ Details

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 146,489	$ 77,840	$ (34,321)
Other comprehensive (loss) income:
Unrealized gain (loss) on derivatives (net of tax of $281, $(746), and $0 for 2023, 2022, and 2021, respectively)	882	(2,342)	0
Foreign currency translation adjustment (net of tax of $90, $(269), and $(309) for 2023, 2022 and 2021, respectively)	281	(845)	(1,000)
Pension and other post-retirement benefits liability adjustments (net of tax of $139, $355, and $3,131 for 2023, 2022 and 2021, respectively)	435	1,115	9,828
Comprehensive income (loss)	148,087	75,768	(25,493)
Less: Comprehensive loss attributable to non-controlling interest	(436)	(336)	(560)
Comprehensive income (loss) attributable to U.S. Silica Holdings, Inc.	$ 148,523	$ 76,104	$ (24,933)

- Definition

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income. Excludes changes in equity resulting from investments by owners and distributions to owners.

+ References + Details

- Definition

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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+ Details

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Sales:
Total sales	$ 1,552,022	$ 1,525,147	$ 1,103,879
Cost of sales (excluding depreciation, depletion and amortization):
Total cost of sales (excluding depreciation, depletion and amortization)	1,020,627	1,070,189	794,983
Operating expenses:
Selling, general and administrative	118,797	143,838	119,628
Depreciation, depletion and amortization	137,259	140,166	161,131
Goodwill and other asset impairments	0	0	202
Total operating expenses	256,056	284,004	280,961
Operating income	275,339	170,954	27,935
Other (expense) income:
Interest expense	(101,709)	(77,598)	(71,157)
Other income, net, including interest income	21,939	10,643	6,146
Total other expense	(79,770)	(66,955)	(65,011)
Income (loss) before income taxes	195,569	103,999	(37,076)
Income tax (expense) benefit	(49,080)	(26,159)	2,755
Net income (loss)	146,489	77,840	(34,321)
Less: Net loss attributable to non-controlling interest	(436)	(336)	(560)
Net income (loss) attributable to U.S. Silica Holdings, Inc.	$ 146,925	$ 78,176	$ (33,761)
Earnings (loss) per share attributable to U.S. Silica Holdings, Inc.:
Basic (in dollars per share)	$ 1.91	$ 1.04	$ (0.45)
Diluted (in dollars per share)	$ 1.87	$ 1.01	$ (0.45)
Weighted average shares outstanding:
Basic (shares)	76,980	75,512	74,350
Diluted (shares)	78,520	77,670	74,350
Dividends declared per share (in dollars per share)	$ 0	$ 0	$ 0
Product
Sales:
Total sales	$ 1,231,594	$ 1,139,773	$ 896,203
Cost of sales (excluding depreciation, depletion and amortization):
Total cost of sales (excluding depreciation, depletion and amortization)	808,706	801,789	633,857
Service
Sales:
Total sales	320,428	385,374	207,676
Cost of sales (excluding depreciation, depletion and amortization):
Total cost of sales (excluding depreciation, depletion and amortization)	$ 211,921	$ 268,400	$ 161,126

Parent Company Financials (Tables)

12 Months Ended

Dec. 31, 2023

Condensed Financial Information Disclosure [Abstract]

Condensed Balance Sheets

U.S. SILICA HOLDINGS, INC.

(PARENT COMPANY ONLY)

CONDENSED BALANCE SHEETS


	December 31,
	2023		2022
	(in thousands)
ASSETS
Current Assets:
Cash and cash equivalents	$	101,378	$	48,398
Other receivables	—		275
Due from affiliates	98,206		160,315
Total current assets	199,584		208,988
Investment in subsidiaries	655,993		495,776
Total assets	$	855,577	$	704,764
LIABILITIES AND STOCKHOLDERS’ EQUITY
Current Liabilities:
Accounts payable and accrued liabilities	$	50	$	50
Dividends payable	—		20
Total current liabilities	50		70
Total liabilities	50		70
Stockholders’ Equity:
Preferred stock	—		—
Common stock	877		854
Additional paid-in capital	1,249,460		1,234,834
Retained deficit	(204,159)		(351,084)
Treasury stock, at cost	(196,745)		(186,196)
Accumulated other comprehensive (loss) income	(125)		(1,723)
Total U.S. Silica Holdings, Inc. stockholders’ equity	849,308		696,685
Non-controlling interest	6,219		8,009
Total stockholders' equity	855,527		704,694
Total liabilities and stockholders’ equity	$	855,577	$	704,764

Condensed Statements of Operations and Comprehensive Income (Loss)

U.S. SILICA HOLDINGS, INC.

(PARENT COMPANY ONLY)

CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS)


	Year ended December 31,
	2023		2022		2021
	(in thousands)
Sales	$	—	$	—	$	—
Cost of sales	—		—		—
Operating expenses
Selling, general and administrative	252		253		252
Total operating expenses	252		253		252
Operating loss	(252)		(253)		(252)
Other income (expense)
Interest income	2,983		565		5
Total other income	2,983		565		5
Income (loss) before income taxes and equity in net earnings of subsidiaries	2,731		312		(247)
Income tax expense	—		—		—
Income (loss) before equity in net earnings of subsidiaries	2,731		312		(247)
Equity in earnings of subsidiaries, net of tax	143,758		77,528		(34,074)
Net income (loss)	$	146,489	$	77,840	$	(34,321)
Less: Net loss attributable to non-controlling interest	(436)		(336)		(560)
Net income (loss) attributable to U.S. Silica Holdings, Inc.	$	146,925	$	78,176	$	(33,761)

Net income (loss)	$	146,489	$	77,840	$	(34,321)
Other comprehensive income (loss)
Unrealized gain (loss) on derivatives (net of tax of $281, $(746), and $0 for 2023, 2022, and 2021, respectively)	882		(2,342)		—
Foreign currency translation adjustment (net of tax of $90, $(269), and $(309) for 2023, 2022 and 2021, respectively)	281		(845)		(1,000)
Pension and other post-retirement benefits liability adjustment (net of tax of $139, $355, and $3,131 for 2023, 2022 and 2021, respectively)	435		1,115		9,828
Comprehensive income (loss)	$	148,087	$	75,768	$	(25,493)
Less: Comprehensive loss attributable to non-controlling interest	(436)		(336)		(560)
Comprehensive income (loss) attributable to U.S. Silica Holdings, Inc.	$	148,523	$	76,104	$	(24,933)

Condensed Statements of Stockholders' Equity

U.S. SILICA HOLDINGS, INC.

(PARENT COMPANY ONLY)

CONDENSED STATEMENTS OF STOCKHOLDERS' EQUITY


(amounts in thousands)	Par Value		Treasury Stock		Additional Paid-In Capital		Retained Deficit - Present		Accumulated Other Comprehensive (Loss) Income		Total U.S. Silica, Inc. Stockholders' Equity		Non-controlling Interest		Total Stockholders’ Equity
Balance at January 1, 2021	$	827	$	(181,615)	$	1,200,023	$	(395,496)	$	(8,479)	$	615,260	$	11,531	$	626,791
Net loss	—		—		—		(33,761)		—		(33,761)		(560)		(34,321)

Foreign currency translation adjustment	—		—		—		—		(1,000)		(1,000)		—		(1,000)
Pension and post-retirement liability	—		—		—		—		9,828		9,828		—		9,828
Cash dividends	—		—		—		(3)		—		(3)		—		(3)
Distributions to non-controlling interest	—		—		—		—		—		—		(1,103)		(1,103)
Common stock-based compensation plans activity:
Equity-based compensation	—		—		18,809		—		—		18,809		—		18,809
Proceeds from options exercised	—		344		(239)		—		—		105		—		105
Shares withheld for employee taxes related to vested restricted stock and stock units	18		(5,023)		(18)		—		—		(5,023)		—		(5,023)

Balance at December 31, 2021	$	845	$	(186,294)	$	1,218,575	$	(429,260)	$	349	$	604,215	$	9,868	$	614,083
Net income	—		—		—		78,176		—		78,176		(336)		77,840
Unrealized loss on derivatives	—		—		—		—		(2,342)		(2,342)		—		(2,342)
Foreign currency translation adjustment	—		—		—		—		(845)		(845)		—		(845)
Pension and post-retirement liability	—		—		—		—		1,115		1,115		—		1,115

Distributions to non-controlling interest	—		—		—		—		—		—		(1,523)		(1,523)
Common stock-based compensation plans activity:
Equity-based compensation	—		—		18,364		—		—		18,364		—		18,364
Proceeds from options exercised	—		3,051		(2,096)		—		—		955		—		955
Shares withheld for employee taxes related to vested restricted stock and stock units	9		(2,953)		(9)		—		—		(2,953)		—		(2,953)
Balance at December 31, 2022	$	854	$	(186,196)	$	1,234,834	$	(351,084)	$	(1,723)	$	696,685	$	8,009	$	704,694
Net income	—		—		—		146,925		—		146,925		(436)		146,489
Unrealized gain on derivatives	—		—		—		—		882		882		—		882
Foreign currency translation adjustment	—		—		—		—		281		281		—		281
Pension and post-retirement liability	—		—		—		—		435		435		—		435

Distributions to non-controlling interest	—		—		—		—		—		—		(1,354)		(1,354)
Common stock-based compensation plans activity:
Equity-based compensation	—		—		14,649		—		—		14,649		—		14,649

Shares withheld for employee taxes related to vested restricted stock and stock units	23		(10,549)		(23)		—		—		(10,549)		—		(10,549)
Balance at December 31, 2023	$	877	$	(196,745)	$	1,249,460	$	(204,159)	$	(125)	$	849,308	$	6,219	$	855,527

Condensed Statements of Cash Flows

U.S. SILICA HOLDINGS, INC.

(PARENT COMPANY ONLY)

CONDENSED STATEMENTS OF CASH FLOWS


	Year ended December 31,
	2023		2022		2021
	(in thousands)
Operating activities:
Net income (loss)	$	146,489	$	77,840	$	(34,321)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Undistributed (income) loss from equity method investment, net	(143,758)		(77,528)		34,074
Changes in assets and liabilities, net of effects of acquisitions:
Other receivables	275		(275)		—
Accounts payable and accrued liabilities	—		—		(236)
Net cash provided by (used in) operating activities	3,006		37		(483)
Investing activities:
Investment in subsidiary	—		—		—
Net cash used in investing activities	—		—		—
Financing activities:
Dividends paid	(23)		(164)		(26)

Proceeds from options exercised	—		955		105
Tax payments related to shares withheld for vested restricted stock and stock units	(10,549)		(2,953)		(5,023)
Distributions to non-controlling interest	(1,354)		(1,523)		(1,103)
Net financing activities with subsidiaries	61,900		5,050		6,675
Net cash provided by financing activities	49,974		1,365		628
Net increase in cash and cash equivalents	52,980		1,402		145
Cash and cash equivalents, beginning of period	48,398		46,996		46,851
Cash and cash equivalents, end of period	$	101,378	$	48,398	$	46,996
Supplemental cash flow information:
Cash received during the period for:
Interest	$	(2,983)	$	(565)	$	(17)

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current Assets:
Cash and cash equivalents	$ 245,716	$ 280,845
Accounts receivable, net	185,917	208,631
Inventories, net	149,429	147,626
Prepaid expenses and other current assets	19,682	20,182
Total current assets	600,744	657,284
Property, plant and mine development, net	1,125,220	1,178,834
Lease right-of-use assets	41,095	42,374
Goodwill	185,649	185,649
Intangible assets, net	131,384	140,809
Other assets	12,501	9,630
Total assets	2,096,593	2,214,580
Current Liabilities:
Accounts payable and accrued liabilities	147,479	216,239
Current portion of operating lease liabilities	18,569	19,773
Current portion of long-term debt	16,367	19,535
Current portion of deferred revenue	3,124	16,275
Income tax payable	311	128
Total current liabilities	185,850	271,950
Long-term debt, net	823,670	1,037,458
Deferred revenue	12,388	14,477
Liability for pension and other post-retirement benefits	28,715	30,911
Deferred income taxes, net	100,458	64,636
Operating lease liabilities	55,089	64,478
Other long-term obligations	34,896	25,976
Total liabilities	1,241,066	1,509,886
Commitments and Contingencies (Note O)
Stockholders’ Equity:
Preferred stock, $0.01 par value, 10,000,000 shares authorized; zero issued and outstanding at December 31, 2023 and 2022	0	0
Common stock, $0.01 par value, 500,000,000 shares authorized; 87,970,110 issued and 77,192,239 outstanding at December 31, 2023; 85,631,109 issued and 75,738,512 outstanding at December 31, 2022	877	854
Additional paid-in capital	1,249,460	1,234,834
Retained deficit	(204,159)	(351,084)
Treasury stock, at cost, 10,777,871 and 9,892,597 shares at December 31, 2023 and 2022, respectively	(196,745)	(186,196)
Accumulated other comprehensive loss	(125)	(1,723)
Total U.S. Silica Holdings, Inc. stockholders’ equity	849,308	696,685
Non-controlling interest	6,219	8,009
Total stockholders' equity	855,527	704,694
Total liabilities and stockholders’ equity	$ 2,096,593	$ 2,214,580

Accumulated Other Comprehensive Income (Loss)

12 Months Ended

Dec. 31, 2023

Equity [Abstract]

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)

NOTE D—ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)

Accumulated Other Comprehensive Income (Loss)

Accumulated other comprehensive income (loss) consists of fair value adjustments associated with cash flow hedges, accumulated adjustments for net experience gains or losses and prior service cost related to employee benefit plans and foreign currency translation adjustments, net of tax. The following table presents the changes in accumulated other comprehensive income (loss) by component (in thousands):


	For the Year Ended December 31, 2023
	Unrealized loss on cash flow hedges		Foreign currency translation adjustments		Pension and other post-retirement benefits liability		Total
Beginning Balance	$	(2,342)	$	(1,262)	$	1,881	$	(1,723)
Other comprehensive income before reclassifications	882		281		1,189		2,352
Amounts reclassed from accumulated other comprehensive loss	—		—		(754)		(754)
Ending Balance	$	(1,460)	$	(981)	$	2,316	$	(125)

Any amounts reclassified from accumulated other comprehensive income (loss) related to pension and other post-retirement benefits are included in the computation of net periodic benefit costs at their pre-tax amounts.

Fair Value Accounting	12 Months Ended
Fair Value Accounting	Dec. 31, 2023
Fair Value Disclosures [Abstract]
FAIR VALUE ACCOUNTING	NOTE L—FAIR VALUE ACCOUNTING Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Fair value is estimated by applying the following hierarchy, which prioritizes the inputs used to measure fair value into three levels and bases the categorization within the hierarchy upon the lowest level of input that is available and significant to the fair value measurement: Level 1—Quoted prices in active markets for identical assets or liabilities. Level 2—Observable inputs other than quoted prices in active markets for identical assets and liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3—Inputs that are generally unobservable and typically reflect management’s estimate of assumptions that market participants would use in pricing the asset or liability. Cash Equivalents Due to the short-term maturity, we believe our cash equivalent instruments at December 31, 2023 and 2022, approximate their reported carrying values, therefore, we have classified our cash equivalents as Level 1 of the fair value hierarchy. Long-Term Debt, Including Current Maturities We believe that the fair values of our long-term debt, including current maturities, approximate their carrying values based on their effective interest rates compared to current market rates, therefore we have classified our long-term debt as Level 1 of the fair value hierarchy. Derivative Instruments The estimated fair value of our derivative instruments is recorded at each reporting period and is determined based on inputs that are readily available in public markets or can be derived from information available in publicly quoted markets. Therefore, we have classified these swap agreements as Level 2 of the fair value hierarchy.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Goodwill and Intangible Assets - Changes in Carrying Amount of Goodwill (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Goodwill [Roll Forward]
Beginning balance	$ 185,649,000	$ 185,649,000
Impairment losses	0	0
Ending balance	185,649,000	185,649,000
Oil & Gas Proppants
Goodwill [Roll Forward]
Beginning balance	0	0
Impairment losses	0	0
Ending balance	0	0
Industrial & Specialty Products
Goodwill [Roll Forward]
Beginning balance	185,649,000	185,649,000
Impairment losses	0	0
Ending balance	$ 185,649,000	$ 185,649,000

- Definition

+ References + Details

Revenue - Changes in Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Unbilled Receivables
Beginning Balance	$ 0	$ 1,957
Reclassifications to billed receivables	0	(4,457)
Revenues recognized in excess of period billings	0	2,500
Ending Balance	0	0
Deferred Revenue
Beginning Balance	30,752	20,741
Revenues recognized from balances held at the beginning of the period	(15,370)	(3,905)
Revenues deferred from period collections on unfulfilled performance obligations	130	27,398
Revenues recognized from period collections	0	(13,482)
Ending Balance	$ 15,512	$ 30,752

Cover - USD ($)	12 Months Ended
Cover - USD ($)	Dec. 31, 2023	Feb. 16, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-35416
Entity Registrant Name	U.S. Silica Holdings, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	26-3718801
Entity Address, Address Line One	24275 Katy Freeway, Suite 600
Entity Address, City or Town	Katy
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77494
City Area Code	281
Local Phone Number	258-2170
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	SLCA
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 891,302,550
Entity Common Stock, Shares Outstanding		78,087,577
Documents Incorporated by Reference	Certain sections of the Proxy Statement for the 2024 Annual Meeting of Shareholders for U.S. Silica Holdings, Inc. (the “2024` Proxy Statement”) are incorporated by reference in Part III of this Annual Report on Form 10-K where indicated.
Amendment Flag	false
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Entity Central Index Key	0001524741

Income Taxes - Income Tax Benefit (Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Current:
Federal	$ (6,603)	$ (1,650)	$ 0
State	(5,936)	(3,078)	(3,353)
Foreign	(1,230)	(491)	(1,385)
Current income tax (expense) benefit	(13,769)	(5,219)	(4,738)
Deferred:
Federal	(32,972)	(17,881)	7,589
State	(2,339)	(3,059)	(96)
Foreign	0	0	0
Deferred income tax (expense) benefit	(35,311)	(20,940)	7,493
Income tax (expense) benefit	$ (49,080)	$ (26,159)	$ 2,755

Accounts Receivable - Narrative (Details)	12 Months Ended
Accounts Receivable - Narrative (Details)	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Customer Concentration Risk \| Sales \| Ten Largest Customers
Concentration Risk [Line Items]
Concentration risk percentage	44.00%	40.00%	40.00%

Goodwill and Intangible Assets - Changes in the Carrying Amount of Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets
Gross Carrying Amount	$ 138,935	$ 138,650
Accumulated Amortization	(72,491)	(62,781)
Net	66,444	75,869
Total Intangible Assets
Gross Carrying Amount	203,875	203,590
Accumulated Amortization	(72,491)	(62,781)
Net	131,384	140,809
Trade names
Indefinite-lived Intangible Assets
Gross Carrying Amount	64,240	64,240
Other
Indefinite-lived Intangible Assets
Gross Carrying Amount	700	700
Technology and intellectual property
Finite-Lived Intangible Assets
Gross Carrying Amount	71,936	71,651
Accumulated Amortization	(34,894)	(29,990)
Net	37,042	41,661
Total Intangible Assets
Accumulated Amortization	(34,894)	(29,990)
Customer relationships
Finite-Lived Intangible Assets
Gross Carrying Amount	66,999	66,999
Accumulated Amortization	(37,597)	(32,791)
Net	29,402	34,208
Total Intangible Assets
Accumulated Amortization	$ (37,597)	$ (32,791)

Debt (Tables)

12 Months Ended

Dec. 31, 2023

Debt Disclosure [Abstract]

Schedule of Debt

Debt (in thousands) consisted of the following:


	December 31, 2023		December 31, 2022
Senior secured credit facility:
Revolver expiring March 23, 2028 (10.21% at December 31, 2023 and 8.44% at December 31, 2022)	$	—	$	—
Term Loan facility—final maturity March 23, 2030 (10.21% at December 31, 2023 and 8.44% December 31, 2022)	868,063		1,059,062
Less: Unamortized original issue discount	(24,183)		(2,035)
Less: Unamortized debt issuance cost	(13,421)		(8,922)
Insurance financing notes payable	6,470		5,628
Finance leases	3,108		3,260
Total debt	840,037		1,056,993
Less: current portion	(16,367)		(19,535)
Total long-term portion of debt	$	823,670	$	1,037,458

Schedule of Contractual Maturities of Debt

At December 31, 2023, contractual maturities of our senior secured Credit Facility (in thousands) are as follows:


2024	$	8,750
2025	8,750
2026	8,750
2027	8,750
2028	8,750
Thereafter	824,313
Total	$	868,063

Equity-Based Compensation - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	0	0	0
Unrecognized compensation expense related to stock options	$ 0	$ 0	$ 0
Restricted Stock and Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	776,339	728,357	881,261
Recognized equity-based compensation	$ 7,600,000	$ 6,800,000	$ 7,300,000
Unrecognized compensation expense related to awards	$ 8,400,000
Recognized weighted-average period	1 year 9 months 18 days
Vesting period for awards of equity instruments	3 years
Granted (dollars per share)	$ 12.16
Restricted Stock and Restricted Stock Units to be Settled in Cash
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity-based compensation	$ 0	$ 900,000	$ 900,000
Vesting period for awards of equity instruments				3 years
Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	1,295,904	920,681	886,091
Recognized equity-based compensation	$ 7,000,000	$ 11,500,000	$ 11,500,000
Unrecognized compensation expense related to awards	$ 7,800,000
Recognized weighted-average period	1 year 8 months 12 days
Vesting period for awards of equity instruments	3 years
Granted (dollars per share)	$ 9.54	$ 11.79	$ 12.04
Performance Shares to be Settled in Cash
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity-based compensation	$ 100,000	$ 1,100,000	$ 700,000
Vesting period for awards of equity instruments				3 years
2011 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock that may be issued (in shares)	4,490,066

Pension and Post-Retirement Benefits - Narrative (Details) $ in Thousands		12 Months Ended
	Nov. 20, 2023 USD ($)	Dec. 31, 2023 USD ($) plan	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Pension Plans, Postretirement and Other Employee Benefits
Defined benefit plan, plan participant	$ 21,600
Excess plan assets	21,600
Pre tax settlement (loss)	$ 1,800
Projected benefit obligation, nonqualified pension plan		$ 1,200	$ 1,200
Defined benefit plan, pension plans with accumulated benefit obligations in excess of plan assets, aggregate accumulated benefit obligation		1,200	1,200
Fair value of plan assets, nonqualified pension plan		0	0
Defined benefit plan, accumulated other comprehensive income net gains (losses), after tax		3,800	6,500
Total amounts in accumulated other comprehensive (loss) income		$ 3,300	$ 5,400
Number of multiemployer defined benefit plans \| plan		3
Percentage of contributions to individual multiemployer funds		5.00%	5.00%	5.00%
Company contributions to defined contribution plan		$ 7,700	$ 6,900	$ 5,900
Certain Employees
Pension Plans, Postretirement and Other Employee Benefits
Company contribution over defined benefit plan		4.00%
All Eligible Employees
Pension Plans, Postretirement and Other Employee Benefits
Company contribution over defined benefit plan		6.00%
Pension Benefits
Pension Plans, Postretirement and Other Employee Benefits
Accumulated benefit obligation		$ 88,600	$ 112,200
Expected contributions to the plans for next fiscal year		4,800
Post-retirement Benefits
Pension Plans, Postretirement and Other Employee Benefits
Expected contributions to the plans for next fiscal year		$ 900

Segment Reporting

12 Months Ended

Dec. 31, 2023

Segment Reporting [Abstract]

SEGMENT REPORTING

NOTE U— SEGMENT REPORTING

Our business is organized into two reportable segments, Oil & Gas Proppants and Industrial & Specialty Products, based on end markets. The reportable segments are consistent with how management views the markets that we serve and the financial information reviewed by the chief operating decision maker. We manage our Oil & Gas Proppants and Industrial & Specialty Products businesses as components of an enterprise for which separate information is available and is evaluated regularly by the chief operating decision maker in deciding how to allocate resources and assess performance.

In the Oil & Gas Proppants segment, we serve the oil and gas recovery market primarily by providing and delivering fracturing sand, or “frac sand,” which is pumped down oil and natural gas wells to prop open rock fissures and increase the flow rate of oil and natural gas from the wells.

The Industrial & Specialty Products segment consists of over 800 product types and materials used in a variety of markets including building and construction products, fillers and extenders, filtration, glassmaking, absorbents, foundry, and sports and recreation.

An operating segment’s performance is primarily evaluated based on segment contribution margin, which excludes selling, general, and administrative costs, corporate costs, plant capacity expansion expenses, and facility closure costs. We believe that segment contribution margin, as defined above, is an appropriate measure for evaluating the operating performance of our segments. However, segment contribution margin is a non-GAAP measure and should be considered in addition to, not a substitute for, or superior to, net income (loss) or other measures of financial performance prepared in accordance with GAAP. The other accounting policies of each of the two reportable segments are the same as those in Note B - Summary of Significant Accounting Policies to these Consolidated Financial Statements.

The following table presents sales and segment contribution margin (in thousands) for the reportable segments and other operating results not allocated to the reported segments:


	Year Ended December 31,
	2023		2022		2021
Sales:
Oil & Gas Proppants	$	994,276	$	961,667	$	615,448
Industrial & Specialty Products	557,746		563,480		488,431
Total sales	1,552,022		1,525,147		1,103,879
Segment contribution margin:
Oil & Gas Proppants	361,998		301,837		160,052
Industrial & Specialty Products	187,665		170,280		168,499
Total segment contribution margin	549,663		472,117		328,551
Operating activities excluded from segment cost of sales	(18,268)		(17,159)		(19,655)
Selling, general and administrative	(118,797)		(143,838)		(119,628)
Depreciation, depletion and amortization	(137,259)		(140,166)		(161,131)
Goodwill and other asset impairments	—		—		(202)
Interest expense	(101,709)		(77,598)		(71,157)
Other income, net, including interest income	21,939		10,643		6,146
Income tax (expense) benefit	(49,080)		(26,159)		2,755
Net income (loss)	$	146,489	$	77,840	$	(34,321)
Less: Net loss attributable to non-controlling interest	(436)		(336)		(560)
Net income (loss) attributable to U.S. Silica Holdings, Inc.	$	146,925	$	78,176	$	(33,761)

Asset information, including capital expenditures and depreciation, depletion, and amortization, by segment is not included in reports used by management in its monitoring of performance and, therefore, is not reported by segment. At both December 31, 2023 and 2022, goodwill of $185.6 million has been allocated to these segments with zero assigned to Oil & Gas Proppants and $185.6 million to Industrial & Specialty Products.

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-15

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 31
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-31

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-42

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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-URI https://asc.fasb.org//1943274/2147482810/280-10-50-40

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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-URI https://asc.fasb.org//280/tableOfContent

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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-URI https://asc.fasb.org//1943274/2147482810/280-10-50-26

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-34

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Revenue - Sales by Major Source (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Total Sales	$ 1,552,022	$ 1,525,147	$ 1,103,879
Oil & Gas Proppants
Disaggregation of Revenue [Line Items]
Total Sales	994,276	961,667	615,448
Industrial & Specialty Products
Disaggregation of Revenue [Line Items]
Total Sales	557,746	563,480	488,431
Product
Disaggregation of Revenue [Line Items]
Total Sales	1,231,594	1,139,773	896,203
Product \| Oil & Gas Proppants
Disaggregation of Revenue [Line Items]
Total Sales	673,848	576,293
Product \| Industrial & Specialty Products
Disaggregation of Revenue [Line Items]
Total Sales	557,746	563,480
Service
Disaggregation of Revenue [Line Items]
Total Sales	320,428	385,374	$ 207,676
Service \| Oil & Gas Proppants
Disaggregation of Revenue [Line Items]
Total Sales	320,428	385,374
Service \| Industrial & Specialty Products
Disaggregation of Revenue [Line Items]
Total Sales	$ 0	$ 0

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References + Details

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 924
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-Section S99
-Paragraph 1
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//1943274/2147479806/606-10-50-4

+ Details

Inventories (Tables)

12 Months Ended

Dec. 31, 2023

Inventory Disclosure [Abstract]

Schedule of Inventories

Inventories (in thousands) consisted of the following:


	December 31, 2023		December 31, 2022
Supplies	$	65,422	$	54,805
Raw materials and work in process	54,142		47,042
Finished goods	29,865		45,779
Total inventories	$	149,429	$	147,626

Derivative Instruments (Tables)

12 Months Ended

Dec. 31, 2023

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of Estimated Fair Values of Derivative Instruments

The following table summarizes the fair value of our derivative instruments (in thousands, except contract/notional amount). See Note L - Fair Value Accounting for more information regarding the estimated fair values of our derivative instruments.


	December 31, 2023						December 31, 2022
	Maturity Date	Contract/Notional Amount (MMBtu)	Carrying Amount		Fair Value		Maturity Date	Contract/Notional Amount	Carrying Amount		Fair Value
Natural Gas - W. Texas (WAHA) - Inside FERC	2023	1,200,000	$	—	$	—	2023	1,200,000	$	(1,887)	$	(1,887)
Natural Gas - W. Texas (WAHA) - Inside FERC	2024	870,000	$	(1,542)	$	(1,542)	2024	870,000	$	(656)	$	(656)
Natural Gas - W. Texas (WAHA) - Inside FERC	2024	750,000	$	(11)	$	(11)	N/A	N/A	$	—	$	—
Natural Gas - Henry Hub - NYMEX	2023	300,000	$	—	$	—	2023	300,000	$	(425)	$	(425)
Natural Gas - Henry Hub - NYMEX	2024	120,000	$	(258)	$	(258)	2024	120,000	$	(85)	$	(85)
Natural Gas - Henry Hub - NYMEX	2025	90,000	$	(115)	$	(115)	2025	90,000	$	(35)	$	(35)

Schedule of Effect of Derivatives Instruments on Combined Statements of Operations and Comprehensive Income

The following table summarizes the effect of derivative instruments (in thousands) on our income statements and our consolidated statements of comprehensive income:


	Year ended December 31,
	2023		2022		2021
Deferred losses from derivatives in OCI, beginning of period	$	(2,342)	$	—	$	—
Gain (loss) recognized in OCI from derivative instruments	882		(2,342)		—

Deferred losses from derivatives in OCI, end of period	$	(1,460)	$	(2,342)	$	—

Income Taxes - Tax Effects on Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Gross deferred tax assets:
Net operating loss carry forward and state tax credits	$ 23,839	$ 54,638
Pension and post-retirement benefit costs	6,214	6,789
Property, plant and equipment	8,210	5,935
Accrued expenses	12,989	18,232
Inventories	369	0
Federal tax credits	0	1,047
Stock-based compensation expense	4,187	6,374
Interest expense limitation	21,685	19,826
Intangibles	4,139	6,366
Lease obligation liability	8,918	11,393
Other	7,406	5,886
Total deferred tax assets	97,956	136,486
Gross deferred tax liabilities:
Land and mineral property basis difference	(130,764)	(124,669)
Fixed assets and depreciation	(67,014)	(74,714)
Inventories	0	(1,170)
Other	(636)	(569)
Total deferred tax liabilities	(198,414)	(201,122)
Net deferred tax liabilities	$ (100,458)	$ (64,636)

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Dec. 31, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2023

Commitments and Contingencies Disclosure [Abstract]

Schedule of Future Minimum Annual Commitments

Future Minimum Annual Commitments (in thousands):


Year ending December 31,	Minimum Purchase Commitments
2024	$	10,124
2025	6,815
2026	4,687
2027	2,288
2028	1,888
Thereafter	5,884
Total future purchase commitments	$	31,686

Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ 704,694	$ 614,083	$ 626,791
Other comprehensive income before reclassifications	2,352
Amounts reclassed from accumulated other comprehensive loss	(754)
Ending Balance	855,527	704,694	614,083
Total
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(1,723)	349	(8,479)
Ending Balance	(125)	(1,723)	349
Unrealized loss on cash flow hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(2,342)	0	0
Other comprehensive income before reclassifications	882	(2,342)	0
Amounts reclassed from accumulated other comprehensive loss	0
Ending Balance	(1,460)	(2,342)	$ 0
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(1,262)
Other comprehensive income before reclassifications	281
Amounts reclassed from accumulated other comprehensive loss	0
Ending Balance	(981)	(1,262)
Pension and other post-retirement benefits liability
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	1,881
Other comprehensive income before reclassifications	1,189
Amounts reclassed from accumulated other comprehensive loss	(754)
Ending Balance	$ 2,316	$ 1,881

- Definition

Amount of equity (deficit) attributable to parent and noncontrolling interest. Excludes temporary equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 24
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-URI https://asc.fasb.org//1943274/2147483421/250-10-45-24

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 30: http://www.xbrl.org/2003/role/disclosureRef
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Reference 31: http://www.xbrl.org/2003/role/disclosureRef
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Reference 38: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 39: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 40: http://www.xbrl.org/2009/role/commonPracticeRef
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+ Details

Goodwill and Intangible Assets

12 Months Ended

Dec. 31, 2023

Goodwill and Intangible Assets Disclosure [Abstract]

GOODWILL AND INTANGIBLE ASSETS

NOTE H—GOODWILL AND INTANGIBLE ASSETS

The changes in the carrying amount of goodwill (in thousands) by business segment consisted of the following:


	Oil & Gas Proppants Segment		Industrial & Specialty Products Segment		Total
Balance at December 31, 2021	$	—	$	185,649	$	185,649

Impairment losses	—		—		—

Balance at December 31, 2022	—		185,649		185,649

Impairment losses	—		—		—
Balance at December 31, 2023	$	—	$	185,649	$	185,649

Goodwill and trade names are evaluated for impairment annually as of October 31, or more frequently when indicators of impairment exist. We evaluated events and circumstances since the date of our last qualitative assessment, including macroeconomic conditions, industry and market conditions, and our overall financial performance. There were no triggering events identified, therefore, no impairment charges were recorded related to goodwill or trade names for the years ended December 31, 2023 and 2022.

The changes in the carrying amount of intangible assets (in thousands) consisted of the following:


	December 31, 2023				December 31, 2022
	Gross Carrying Amount		Accumulated Amortization		Net		Gross Carrying Amount		Accumulated Amortization		Net

Technology and intellectual property	$	71,936	$	(34,894)	$	37,042	$	71,651	$	(29,990)	$	41,661
Customer relationships	66,999		(37,597)		29,402		66,999		(32,791)		34,208
Total definite-lived intangible assets:	$	138,935	$	(72,491)	$	66,444	$	138,650	$	(62,781)	$	75,869
Trade names	64,240		—		64,240		64,240		—		64,240
Other	700		—		700		700		—		700
Total intangible assets:	$	203,875	$	(72,491)	$	131,384	$	203,590	$	(62,781)	$	140,809

Estimated useful life of technology and intellectual property is 15 years. Estimated useful life of customer relationships is a range of 13 - 20 years.

Amortization expense was $9.7 million, $9.7 million and $9.7 million for the years ended December 31, 2023, 2022, and 2021, respectively.

At December 31, 2023, the estimated amortization expense related to definite-lived intangible assets (in thousands) for the five succeeding years is as follows:


2024	$	9,717
2025	$	9,716
2026	$	9,716
2027	$	9,716
2028	$	9,676

Parent Company Financials

12 Months Ended

Dec. 31, 2023

Condensed Financial Information Disclosure [Abstract]

PARENT COMPANY FINANCIALS

NOTE V— PARENT COMPANY FINANCIALS

U.S. SILICA HOLDINGS, INC.

(PARENT COMPANY ONLY)

CONDENSED BALANCE SHEETS


	December 31,
	2023		2022
	(in thousands)
ASSETS
Current Assets:
Cash and cash equivalents	$	101,378	$	48,398
Other receivables	—		275
Due from affiliates	98,206		160,315
Total current assets	199,584		208,988
Investment in subsidiaries	655,993		495,776
Total assets	$	855,577	$	704,764
LIABILITIES AND STOCKHOLDERS’ EQUITY
Current Liabilities:
Accounts payable and accrued liabilities	$	50	$	50
Dividends payable	—		20
Total current liabilities	50		70
Total liabilities	50		70
Stockholders’ Equity:
Preferred stock	—		—
Common stock	877		854
Additional paid-in capital	1,249,460		1,234,834
Retained deficit	(204,159)		(351,084)
Treasury stock, at cost	(196,745)		(186,196)
Accumulated other comprehensive (loss) income	(125)		(1,723)
Total U.S. Silica Holdings, Inc. stockholders’ equity	849,308		696,685
Non-controlling interest	6,219		8,009
Total stockholders' equity	855,527		704,694
Total liabilities and stockholders’ equity	$	855,577	$	704,764

U.S. SILICA HOLDINGS, INC.

(PARENT COMPANY ONLY)

CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS)


	Year ended December 31,
	2023		2022		2021
	(in thousands)
Sales	$	—	$	—	$	—
Cost of sales	—		—		—
Operating expenses
Selling, general and administrative	252		253		252
Total operating expenses	252		253		252
Operating loss	(252)		(253)		(252)
Other income (expense)
Interest income	2,983		565		5
Total other income	2,983		565		5
Income (loss) before income taxes and equity in net earnings of subsidiaries	2,731		312		(247)
Income tax expense	—		—		—
Income (loss) before equity in net earnings of subsidiaries	2,731		312		(247)
Equity in earnings of subsidiaries, net of tax	143,758		77,528		(34,074)
Net income (loss)	$	146,489	$	77,840	$	(34,321)
Less: Net loss attributable to non-controlling interest	(436)		(336)		(560)
Net income (loss) attributable to U.S. Silica Holdings, Inc.	$	146,925	$	78,176	$	(33,761)

Net income (loss)	$	146,489	$	77,840	$	(34,321)
Other comprehensive income (loss)
Unrealized gain (loss) on derivatives (net of tax of $281, $(746), and $0 for 2023, 2022, and 2021, respectively)	882		(2,342)		—
Foreign currency translation adjustment (net of tax of $90, $(269), and $(309) for 2023, 2022 and 2021, respectively)	281		(845)		(1,000)
Pension and other post-retirement benefits liability adjustment (net of tax of $139, $355, and $3,131 for 2023, 2022 and 2021, respectively)	435		1,115		9,828
Comprehensive income (loss)	$	148,087	$	75,768	$	(25,493)
Less: Comprehensive loss attributable to non-controlling interest	(436)		(336)		(560)
Comprehensive income (loss) attributable to U.S. Silica Holdings, Inc.	$	148,523	$	76,104	$	(24,933)

U.S. SILICA HOLDINGS, INC.

(PARENT COMPANY ONLY)

CONDENSED STATEMENTS OF STOCKHOLDERS' EQUITY


(amounts in thousands)	Par Value		Treasury Stock		Additional Paid-In Capital		Retained Deficit - Present		Accumulated Other Comprehensive (Loss) Income		Total U.S. Silica, Inc. Stockholders' Equity		Non-controlling Interest		Total Stockholders’ Equity
Balance at January 1, 2021	$	827	$	(181,615)	$	1,200,023	$	(395,496)	$	(8,479)	$	615,260	$	11,531	$	626,791
Net loss	—		—		—		(33,761)		—		(33,761)		(560)		(34,321)

Foreign currency translation adjustment	—		—		—		—		(1,000)		(1,000)		—		(1,000)
Pension and post-retirement liability	—		—		—		—		9,828		9,828		—		9,828
Cash dividends	—		—		—		(3)		—		(3)		—		(3)
Distributions to non-controlling interest	—		—		—		—		—		—		(1,103)		(1,103)
Common stock-based compensation plans activity:
Equity-based compensation	—		—		18,809		—		—		18,809		—		18,809
Proceeds from options exercised	—		344		(239)		—		—		105		—		105
Shares withheld for employee taxes related to vested restricted stock and stock units	18		(5,023)		(18)		—		—		(5,023)		—		(5,023)

Balance at December 31, 2021	$	845	$	(186,294)	$	1,218,575	$	(429,260)	$	349	$	604,215	$	9,868	$	614,083
Net income	—		—		—		78,176		—		78,176		(336)		77,840
Unrealized loss on derivatives	—		—		—		—		(2,342)		(2,342)		—		(2,342)
Foreign currency translation adjustment	—		—		—		—		(845)		(845)		—		(845)
Pension and post-retirement liability	—		—		—		—		1,115		1,115		—		1,115

Distributions to non-controlling interest	—		—		—		—		—		—		(1,523)		(1,523)
Common stock-based compensation plans activity:
Equity-based compensation	—		—		18,364		—		—		18,364		—		18,364
Proceeds from options exercised	—		3,051		(2,096)		—		—		955		—		955
Shares withheld for employee taxes related to vested restricted stock and stock units	9		(2,953)		(9)		—		—		(2,953)		—		(2,953)
Balance at December 31, 2022	$	854	$	(186,196)	$	1,234,834	$	(351,084)	$	(1,723)	$	696,685	$	8,009	$	704,694
Net income	—		—		—		146,925		—		146,925		(436)		146,489
Unrealized gain on derivatives	—		—		—		—		882		882		—		882
Foreign currency translation adjustment	—		—		—		—		281		281		—		281
Pension and post-retirement liability	—		—		—		—		435		435		—		435

Distributions to non-controlling interest	—		—		—		—		—		—		(1,354)		(1,354)
Common stock-based compensation plans activity:
Equity-based compensation	—		—		14,649		—		—		14,649		—		14,649

Shares withheld for employee taxes related to vested restricted stock and stock units	23		(10,549)		(23)		—		—		(10,549)		—		(10,549)
Balance at December 31, 2023	$	877	$	(196,745)	$	1,249,460	$	(204,159)	$	(125)	$	849,308	$	6,219	$	855,527

U.S. SILICA HOLDINGS, INC.

(PARENT COMPANY ONLY)

CONDENSED STATEMENTS OF CASH FLOWS


	Year ended December 31,
	2023		2022		2021
	(in thousands)
Operating activities:
Net income (loss)	$	146,489	$	77,840	$	(34,321)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Undistributed (income) loss from equity method investment, net	(143,758)		(77,528)		34,074
Changes in assets and liabilities, net of effects of acquisitions:
Other receivables	275		(275)		—
Accounts payable and accrued liabilities	—		—		(236)
Net cash provided by (used in) operating activities	3,006		37		(483)
Investing activities:
Investment in subsidiary	—		—		—
Net cash used in investing activities	—		—		—
Financing activities:
Dividends paid	(23)		(164)		(26)

Proceeds from options exercised	—		955		105
Tax payments related to shares withheld for vested restricted stock and stock units	(10,549)		(2,953)		(5,023)
Distributions to non-controlling interest	(1,354)		(1,523)		(1,103)
Net financing activities with subsidiaries	61,900		5,050		6,675
Net cash provided by financing activities	49,974		1,365		628
Net increase in cash and cash equivalents	52,980		1,402		145
Cash and cash equivalents, beginning of period	48,398		46,996		46,851
Cash and cash equivalents, end of period	$	101,378	$	48,398	$	46,996
Supplemental cash flow information:
Cash received during the period for:
Interest	$	(2,983)	$	(565)	$	(17)

Notes to Condensed Financial Statements of Registrant (Parent Company Only)

These condensed parent company only financial statements have been prepared in accordance with Rule 12-04, Schedule I of Regulation S-X, because the restricted net assets of the subsidiaries of U.S. Silica Holdings, Inc. (as defined in Rule 4-08(e)(3) of Regulation S-X) exceed 25% of our consolidated net assets. The ability of our operating subsidiaries to pay dividends may be restricted due to the terms of our Credit Facility, as discussed in Note J - Debt to these financial statements.

These condensed parent company financial statements have been prepared using the same accounting principles and policies described in the notes to the consolidated financial statements; the only exceptions are that (a) the parent company accounts for its subsidiaries using the equity method of accounting, (b) taxes are allocated to the parent from the subsidiary using the separate return method, and (c) intercompany loans are not eliminated. In the parent company financial statements, our investment in subsidiaries is stated at cost plus equity in undistributed earnings of subsidiaries since the date of acquisition. These condensed parent company financial statements should be read in conjunction with our consolidated financial statements and related notes thereto included elsewhere in this report.

No cash dividends were paid to the parent by its consolidated entities for the years presented in the condensed financial statements.

Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Percent or reporting unit fair value less than carrying value	50.00%
Self-insurance reserves	$ 5.0	$ 5.6
Self-insurance reserves classified as current	$ 1.7	$ 1.8
Restricted Stock and Restricted Stock Units
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Vesting period for awards of equity instruments	3 years
Performance Share Units
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Vesting period for awards of equity instruments	3 years
Performance Share Units \| Certain Employees
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Vesting period for awards of equity instruments	3 years
Intellectual property
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful live of finite-lived intangible assets	15 years
Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Self-insurance retention amount	$ 0.1
Minimum \| Supply Agreement
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred revenue, average initial contract term	1 year
Minimum \| Customer relationships
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful live of finite-lived intangible assets	13 years
Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Self-insurance retention amount	$ 0.5
Maximum \| Supply Agreement
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred revenue, average initial contract term	15 years
Maximum \| Customer relationships
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful live of finite-lived intangible assets	20 years
Buildings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful lives of property, plant and mine equipment	15 years
Land improvements
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful lives of property, plant and mine equipment	10 years
Machinery and equipment \| Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful lives of property, plant and mine equipment	3 years
Machinery and equipment \| Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful lives of property, plant and mine equipment	10 years
Furniture and fixtures
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful lives of property, plant and mine equipment	8 years

Equity-Based Compensation - stock option exercise activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-Based Payment Arrangement [Abstract]
Stock options exercised (in shares)	0	90,000	10,164
Intrinsic value of options exercised	$ 0	$ 613	$ 44
Cash received from options exercised	0	955	105
Tax benefit realized from stock options exercised	$ 0	$ 148	$ 11

Accounts Receivable

12 Months Ended

Dec. 31, 2023

Receivables [Abstract]

ACCOUNTS RECEIVABLE

NOTE E—ACCOUNTS RECEIVABLE

Accounts receivable (in thousands) consisted of the following:


	December 31, 2023		December 31, 2022
Trade receivables	$	190,189	$	209,683
Less: Allowance for credit losses	(5,323)		(5,691)
Net trade receivables	184,866		203,992
Other receivables	1,051		4,639
Total accounts receivable	$	185,917	$	208,631

We classify our trade receivables into the following portfolio segments: Oil & Gas Proppants and Industrial & Specialty Products, which also aligns with our reporting segments. We estimate the allowance for credit losses based on historical collection trends, the age of outstanding receivables, risks attributable to specific customers, such as credit history, bankruptcy or other going concern issues, and current economic and industry conditions. If events or circumstances indicate that specific receivable balances may be impaired, further consideration is given to the collectability of those balances and the allowance is adjusted accordingly. Past due balances are written off when we have exhausted our internal and external collection efforts and have been unsuccessful in collecting the amount due.

The following table reflects the change of the allowance for credit losses (in thousands) disaggregated by portfolio segments:


	Oil & Gas Proppants		Industrial & Specialty Products		Total
Beginning balance, December 31, 2022	$	4,028	$	1,663	$	5,691
Allowance for credit losses	—		(103)		(103)
Recoveries	95		—		95
Write-offs	(300)		(60)		(360)
Ending balance, December 31, 2023	$	3,823	$	1,500	$	5,323

Our ten largest customers accounted for approximately 44%, 40% and 40% of total sales during the years ended December 31, 2023, 2022 and 2021, respectively. No single customer accounted for more than 10% of our total sales during the years ended December 31, 2023, 2022 and 2021. At December 31, 2023 and 2022, none of our customers' accounts receivable represented 10% or more of our total trade accounts receivable.

Debt - Narrative (Details)			3 Months Ended	12 Months Ended
Debt - Narrative (Details)	Mar. 23, 2023 USD ($)	Mar. 22, 2023 USD ($)	Sep. 30, 2023	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	May 01, 2018
Debt Instrument [Line Items]
Debt issuance amortization				$ 3,105,000	$ 4,815,000	$ 5,059,000
Repayments of long-term debt				190,999,000	$ 158,064,000	$ 12,800,000
Term Loan facility—final maturity March 23, 2030 (10.21% at December 31, 2023 and 8.44% December 31, 2022) \| Discount Rate 97%
Debt Instrument [Line Items]
Debt redemption price percentage					97.00%
Term Loan facility—final maturity March 23, 2030 (10.21% at December 31, 2023 and 8.44% December 31, 2022) \| Discount Rate 96.25%
Debt Instrument [Line Items]
Debt redemption price percentage					96.25%
Term Loan facility—final maturity March 23, 2030 (10.21% at December 31, 2023 and 8.44% December 31, 2022) \| Secured Debt
Debt Instrument [Line Items]
Credit facility consolidated total net leverage ratio							4.00
Revolver expiring March 23, 2028 (10.21% at December 31, 2023 and 8.44% at December 31, 2022) \| Revolver
Debt Instrument [Line Items]
Available borrowing base				150,000,000
Amount drawn under credit facility				0
Amount available under credit facility				134,700,000
Revolver expiring March 23, 2028 (10.21% at December 31, 2023 and 8.44% at December 31, 2022) \| Letter of Credit
Debt Instrument [Line Items]
Amount allocated for letters of credit				$ 15,300,000
Current consolidated leverage ratio				1.91
Insurance financing notes payable \| Notes Payable
Debt Instrument [Line Items]
Notes payable balance				$ 6,500,000
Debt stated interest rate			6.60%
Debt term			9 months
Secured Debt
Debt Instrument [Line Items]
Debt issued	$ 1,100,000,000
Capitalized debt issuance costs	45,900,000
Gain (loss) on extinguishment of debt	(4,300,000)
Secured Debt \| Term Loan facility—final maturity March 23, 2030 (10.21% at December 31, 2023 and 8.44% December 31, 2022)
Debt Instrument [Line Items]
Debt issued	950,000,000
Gain (loss) on extinguishment of debt		$ (1,000,000)			$ 2,900,000
Debt repurchased		109,000,000
Debt issuance amortization		$ 1,000,000		3,200,000	1,800,000
Repayments of long-term debt				$ 75,000,000
Secured Debt \| Term Loan facility—final maturity March 23, 2030 (10.21% at December 31, 2023 and 8.44% December 31, 2022) \| Discount Rate 97%
Debt Instrument [Line Items]
Debt repurchased					100,000,000
Secured Debt \| Term Loan facility—final maturity March 23, 2030 (10.21% at December 31, 2023 and 8.44% December 31, 2022) \| Discount Rate 96.25%
Debt Instrument [Line Items]
Debt repurchased					$ 50,000,000
Secured Debt \| Revolver expiring March 23, 2028 (10.21% at December 31, 2023 and 8.44% at December 31, 2022) \| Revolver
Debt Instrument [Line Items]
Available borrowing base	$ 150,000,000
Secured Debt \| Revolver expiring March 23, 2028 (10.21% at December 31, 2023 and 8.44% at December 31, 2022) \| Secured Debt
Debt Instrument [Line Items]
Net leverage ratio, credit facility threshold percentage							0.35

Pension and Post-Retirement Benefits

12 Months Ended

Dec. 31, 2023

Retirement Benefits [Abstract]

PENSION AND POST-RETIREMENT BENEFITS

NOTE P— PENSION AND POST-RETIREMENT BENEFITS

We maintain a single-employer noncontributory defined benefit pension plan covering certain employees. The plan is frozen to all new employees. The plan provides benefits based on each covered employee’s years of qualifying service. Our funding policy is to contribute amounts within the range of the minimum required and maximum deductible contributions for the plan consistent with a goal of appropriate minimization of the unfunded projected benefit obligations. The pension plan uses a benefit level per year of service for covered hourly employees and a final average pay method for covered salaried employees. The plan uses the projected unit credit cost method to determine the actuarial valuation.

We employ a total rate of return investment approach whereby a mix of equities and fixed income investments are used to maximize the long-term return of plan assets for a prudent level of risk. Risk tolerance is established through careful consideration of plan liabilities, plan funded status, and corporate financial condition. The investment portfolio contains a diversified blend of equity and fixed-income investments. Furthermore, equity investments are diversified across U.S. and non-U.S. stocks, as well as growth, value and small and large capitalizations. Investment risk is measured and monitored on an ongoing basis through quarterly investment portfolio reviews, annual liability measurements, and periodic asset/liability studies.

We employ a building block approach in determining the long-term rate of return for plan assets. Historical markets are studied and long-term historical relationships between equities and fixed-income are preserved consistent with the widely accepted capital market principle that assets with higher volatility generate a greater return over the long run. Current market factors such as inflation and interest rates are evaluated before long-term capital market assumptions are determined. The long-term portfolio return is established via a building block approach with proper consideration of diversification and rebalancing. Peer data and historical returns are reviewed to check for reasonability and appropriateness.

In addition, we provide defined benefit post-retirement health care and life insurance benefits to some employees. Covered employees become eligible for these benefits at retirement after meeting minimum age and service requirements. The projected future cost of providing post-retirement benefits, such as healthcare and life insurance, is recognized as an expense as employees render services. In general, retiree health benefits are paid as covered expenses are incurred.

Net pension benefit cost (in thousands) consisted of the following:


	Year Ended December 31,
	2023		2022		2021
Service cost	$	2,325	$	2,516	$	2,855
Interest cost	5,343		3,120		2,619
Expected return on plan assets	(6,373)		(5,887)		(5,688)
Settlement loss	1,803		—		—
Net amortization and deferral	41		2,249		3,212
Net pension benefit costs	$	3,139	$	1,998	$	2,998

Net post-retirement benefit cost (in thousands) consisted of the following:


	Year Ended December 31,
	2023		2022		2021
Service cost	$	8	$	18	$	24
Interest cost	332		180		141
Unrecognized prior service cost	(2,063)		—		—
Unrecognized net gain	(792)		(2,360)		(2,204)
Net post-retirement benefit costs	$	(2,515)	$	(2,162)	$	(2,039)

The changes in benefit obligations and plan assets (in thousands), as well as the funded status (in thousands) of our pension and post-retirement plans were as follows:


	Pension Benefits				Post-retirement Benefits
	2023		2022		2023		2022
Benefit obligation at January 1,	$	112,247	$	144,251	$	7,577	$	9,391
Service cost	2,325		2,516		8		18
Interest cost	5,343		3,120		332		180
Actuarial loss (gain)	2		(28,494)		(552)		(1,566)
Benefits paid	(31,352)		(9,486)		(469)		(504)

Other	74		340		34		58
Benefit obligation at December 31,	$	88,639	$	112,247	$	6,930	$	7,577
Fair value of plan assets at January 1,	$	88,919	$	120,911	$	—	$	—
Actual return on plan assets	7,497		(22,507)		—		—
Employer contributions	2,000		—		435		446
Benefits paid	(31,352)		(9,486)		(469)		(504)
Other	—		1		34		58
Fair value of plan assets at December 31,	$	67,064	$	88,919	$	—	$	—
Plan assets less than benefit obligations at December 31 recognized as liability for pension and other post-retirement benefits	$	(21,575)	$	(23,328)	$	(6,930)	$	(7,577)

The accumulated benefit obligation for the defined benefit pension plans, which excludes the assumption of future salary increases, totaled $88.6 million and $112.2 million at December 31, 2023 and 2022, respectively. We record components other than service costs in Other income, net, including interest income in the Consolidated Statements of Operations.

On November 20, 2023, U.S. Silica Company entered into a commitment agreement with subsidiaries of Securian Financial (Securian) under which U.S. Silica Company agreed to purchase nonparticipating single premium group annuity contracts that would transfer to Securian approximately $21.6 million of the Plan’s defined benefit pension obligations related to certain retirees, participants and beneficiaries under the Plan.

The purchase of the group annuity contracts covers approximately 521 U.S. Silica Company participants and beneficiaries (Transferred Participants). Under the group annuity contracts, Securian, through its wholly-owned subsidiary Minnesota Life Insurance Company, made an irrevocable commitment, and will be solely responsible, to pay the pension benefits of each Transferred Participant beginning with their January 2024 pension payments. The transaction does not change the amount of pension benefits payable to the Transferred Participants.

The purchase of the group annuity contracts was funded directly by assets of the Plan via the pension trust underlying the Plan and required no cash or asset contributions by U.S. Silica Company. We transferred approximately $21.6 million of pension benefit obligation and related plan assets upon close of the transaction and recognized a pre-tax pension settlement loss of $1.8 million. The funded status of the Plan did not materially change due to this transaction.

We also sponsor unfunded, nonqualified pension plans. The projected benefit obligation, accumulated benefit obligation and fair value of plan assets for these plans were $1.2 million, $1.2 million and zero, respectively, at both December 31, 2023 and December 31, 2022.

Future estimated annual benefit payments (in thousands) for pension and post-retirement benefit obligations were as follows:


	Benefits
			Post-retirement
	Pension		Before Medicare Subsidy		After Medicare Subsidy
2024	$	7,159	$	864	$	864
2025	7,117		776		776
2026	7,145		711		711
2027	7,051		659		659
2028	6,966		596		596
2029-2033	32,951		2,400		2,400

Our best estimate of expected contributions to the pension and post-retirement medical benefit plans for the 2024 fiscal year are $4.8 million and $0.9 million, respectively.

The total amounts in accumulated other comprehensive income (loss) related to net actuarial loss for the pension and post-retirement plans were $3.8 million and $6.5 million as of December 31, 2023 and 2022, respectively. The total amounts in accumulated other comprehensive income (loss) related to prior service cost for the pension and post-retirement plans, were gains of $3.3 million and $5.4 million as of December 31, 2023 and 2022, respectively.

The actuarial gains in 2023 and 2022 were primarily driven by the change in discount rates on the U.S. qualified plan and postretirement medical plans. The impact of the discount rate change was partially offset by the actual return on plan assets exceeding the expected return on plan assets.

The following weighted-average assumptions were used to determine our obligations under the plans:

Pension Benefits

Post-retirement Benefits

2023

2022

2023

2022

Discount rate

5.0

5.2

4.9

5.1

Long-term rate of compensation increase

N/A

Long-term rate of return on plan assets

7.3

6.0%

N/A

Health care cost trend rate:

Pre-65 initial rate/ultimate rate

N/A

7.3%/4.5%

6.8%/4.5%

Pre-65 ultimate year

N/A

2032

2031

Post-65 initial rate/ultimate rate

N/A

N/A/N/A

Post-65 ultimate year

N/A

The weighted average discount rates used to determine the projected pension and post-retirement obligations were updated to reflect the expected long-term rates of return with maturities comparable to payments for the plan obligations utilizing Aon Hewitt's AA Above Medium Curve.

Mortality tables used for pension benefits and post-retirement benefits plans were the following:


	Pension and Post-retirement Benefits
	2023	2022
Healthy Lives	Pri-2012 base mortality tables with generational mortality improvements using Scale MP-2021	Pri-2012 base mortality tables with generational mortality improvements using Scale MP-2021
Disabled Lives	Pri-2012 base mortality tables with generational mortality improvements using Scale MP-2021	Pri-2012 base mortality tables with generational mortality improvements using Scale MP-2021

The major investment categories and their relative percentage of the fair value of total plan assets as invested were as follows:


	Pension Benefits				Post-retirement Benefits(1)
	2023		2022		2023		2022
Equity securities	54.1	%	54.3	%	—	%	—	%
Debt securities	43.4	%	44.2	%	—	%	—	%
Cash	2.5	%	1.5	%	—	%	—	%


(1)Retiree health benefits are paid by the Company as covered expenses are incurred.

The fair values of the pension plan assets (in thousands) at December 31, 2023, by asset category, were as follows:


	Level 1		Level 2		Level 3		Total
Cash and cash equivalents	$	—	$	1,652	$	—	$	1,652
Mutual funds:
Diversified emerging markets	2,960		—		—		2,960
Foreign large blend	11,707		—		—		11,707
Large-cap blend	11,685		—		—		11,685
Mid-cap blend	6,763		—		—		6,763
Real estate	3,204		—		—		3,204

Fixed income securities:
Corporate notes and bonds	17,768		—		—		17,768
U.S. Treasuries	5,012		—		—		5,012
Mortgage-backed securities	—		3,250		—		3,250
Asset-backed securities	—		3,063		—		3,063


Net asset	$	59,099	$	7,965	$	—	$	67,064

The fair values of the pension plan assets (in thousands) at December 31, 2022, by asset category, were as follows:


	Level 1		Level 2		Level 3		Total
Cash and cash equivalents	$	—	$	1,362	$	—	$	1,362
Mutual funds:
Diversified emerging markets	4,221		—		—		4,221
Foreign large blend	16,740		—		—		16,740
Large-cap blend	15,464		—		—		15,464
Mid-cap blend	7,720		—		—		7,720
Real assets	4,144		—		—		4,144
Fixed income securities:
Corporate notes and bonds	27,892		—		—		27,892
U.S. Treasuries	5,223		—		—		5,223
Mortgage-backed securities	—		3,000		—		3,000
Asset-backed securities	—		3,153		—		3,153

Net asset	$	81,404	$	7,515	$	—	$	88,919

We contribute to three multiemployer defined benefit pension plans under the terms of collective-bargaining agreements for union-represented employees. A multiemployer plan is subject to collective bargaining for employees of two or more unrelated companies. These plans allow multiple employers to pool their pension resources and realize efficiencies associated with the daily administration of the plan. Multiemployer plans are generally governed by a board of trustees composed of management and labor representatives and are funded through employer contributions. However, in most cases, management is not directly represented.

The risks of participating in multiemployer plans differ from single employer plans as follows: 1) assets contributed to a multiemployer plan by one employer may be used to provide benefits to employees of other participating employers, 2) if a participating employer stops contributing to the plan, the unfunded obligations of the plan may be borne by the remaining participating employers, and 3) if we cease to have an obligation to contribute to one or more of the multiemployer plans to which we contribute, we may be required to pay those plans an amount based on the underfunded status of the plan, referred to as a withdrawal liability.

A summary of each multiemployer pension plan for which we participate is presented below:

Pension
Fund

EIN/ Pension
Plan No.

Pension Protection Act

Zone Status(1)

FIP/RP Status
Pending/
Implemented

Company
Contributions
(in thousands)

Surcharge
Imposed

Expiration
Date of
CBA

2023

2022

2023

2022

2021

LIUNA

52-6074345/001

Green

406

395

378

6/7/2025

IUOE

36-6052390/001

Green

349

376

328

8/1/2027

CSSS(2)

36-6044243/001

Red

Yes

(1)The Pension Protection Act of 2006 defines the zone status as follows: green—healthy, yellow—endangered, orange—seriously endangered and red—critical.

Our contributions to individual multiemployer pension funds did not exceed 5% of the fund’s total contributions for the years ended December 31, 2023, 2022 and 2021. Additionally, our contributions to multiemployer post-retirement benefit plans were immaterial for all periods presented in the accompanying consolidated financial statements.

We also sponsor a defined contribution plan covering certain employees. We contribute to the plan in two ways. For certain employees not covered by the defined benefit plan, we make a contribution equal to 4% of their salary. For all other eligible employees, we make a contribution of up to 6% of eligible earnings. Contributions were $7.7 million, $6.9 million and $5.9 million for the years ended December 31, 2023, 2022 and 2021, respectively.

- Definition

The entire disclosure for retirement benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 70
-Name Accounting Standards Codification
-Section 50
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-URI https://asc.fasb.org//1943274/2147480794/715-70-50-1

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
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-URI https://asc.fasb.org//1943274/2147480482/715-20-55-17

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
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-Name Accounting Standards Codification
-Section 50
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-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
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-URI https://asc.fasb.org//1943274/2147480126/715-20-S99-2

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480266/715-60-50-3

+ Details

Earnings Per Share - Antidilutive Securities Excluded From Calculation of Diluted Earnings (Loss) Per Common Share (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Potentially dilutive shares excluded
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from the calculation of diluted earnings (loss) per common share (shares)	0	0	1,714
Stock options excluded
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from the calculation of diluted earnings (loss) per common share (shares)	349	509	667
Restricted stock and performance share units awards excluded
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from the calculation of diluted earnings (loss) per common share (shares)	48	36	66

Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
Income Taxes - Narrative (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Loss Carryforwards [Line Items]
Alternative minimum tax credit carry forward	$ 50,500,000
Unrecognized tax benefits	0	$ 856,000	$ 856,000	$ 0
Interest and penalties related to uncertain tax penalties	0	500,000	400,000
Unrecognized tax benefits, income tax penalties and interest accrued	0	$ 100,000	$ 400,000
IRS
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 74,600,000

Accumulated Other Comprehensive Income (Loss) (Tables)

12 Months Ended

Dec. 31, 2023

Equity [Abstract]

Schedule of Changes in Accumulated Other Comprehensive Income (Loss)

The following table presents the changes in accumulated other comprehensive income (loss) by component (in thousands):


	For the Year Ended December 31, 2023
	Unrealized loss on cash flow hedges		Foreign currency translation adjustments		Pension and other post-retirement benefits liability		Total
Beginning Balance	$	(2,342)	$	(1,262)	$	1,881	$	(1,723)
Other comprehensive income before reclassifications	882		281		1,189		2,352
Amounts reclassed from accumulated other comprehensive loss	—		—		(754)		(754)
Ending Balance	$	(1,460)	$	(981)	$	2,316	$	(125)

Leases - Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Total leased assets	Total leased assets
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Total leased assets	Total leased assets
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Current portion of long-term debt	Current portion of long-term debt
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Long-term debt, net	Long-term debt, net
Assets
Operating	$ 37,890	$ 39,088
Finance	3,205	3,286
Total leased assets	41,095	42,374
Current
Operating	18,569	19,773
Finance	1,147	1,107
Non-Current
Operating	55,089	64,478
Finance	1,961	2,153
Total lease liabilities	$ 76,766	$ 87,511
Weighted average remaining lease term:
Operating leases	6 years 2 months 12 days	6 years 4 months 24 days
Finance leases	4 years 9 months 18 days	4 years 4 months 24 days
Weighted average discount rate:
Operating leases	6.30%	5.70%
Finance leases	6.60%	5.10%

Parent Company Financials - Condensed Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Current Assets:
Cash and cash equivalents	$ 245,716	$ 280,845
Total current assets	600,744	657,284
Total assets	2,096,593	2,214,580
Current Liabilities:
Accounts payable and accrued liabilities	147,479	216,239
Total current liabilities	185,850	271,950
Total liabilities	1,241,066	1,509,886
Stockholders’ Equity:
Preferred stock	0	0
Common stock	877	854
Additional paid-in capital	1,249,460	1,234,834
Retained deficit	(204,159)	(351,084)
Treasury stock, at cost	(196,745)	(186,196)
Accumulated other comprehensive (loss) income	(125)	(1,723)
Total U.S. Silica Holdings, Inc. stockholders’ equity	849,308	696,685
Non-controlling interest	6,219	8,009
Total stockholders' equity	855,527	704,694	$ 614,083	$ 626,791
Total liabilities and stockholders’ equity	2,096,593	2,214,580
Parent Company
Current Assets:
Cash and cash equivalents	101,378	48,398
Total current assets	199,584	208,988
Investment in subsidiaries	655,993	495,776
Total assets	855,577	704,764
Current Liabilities:
Accounts payable and accrued liabilities	50	50
Dividends payable	0	20
Total current liabilities	50	70
Total liabilities	50	70
Stockholders’ Equity:
Preferred stock	0	0
Common stock	877	854
Additional paid-in capital	1,249,460	1,234,834
Retained deficit	(204,159)	(351,084)
Treasury stock, at cost	(196,745)	(186,196)
Accumulated other comprehensive (loss) income	(125)	(1,723)
Total U.S. Silica Holdings, Inc. stockholders’ equity	849,308	696,685
Non-controlling interest	6,219	8,009
Total stockholders' equity	855,527	704,694	$ 614,083	$ 626,791
Total liabilities and stockholders’ equity	855,577	704,764
Parent Company \| Nonrelated Party
Current Assets:
Other receivables	0	275
Parent Company \| Related Party
Current Assets:
Other receivables	$ 98,206	$ 160,315

Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2023

Asset Retirement Obligation Disclosure [Abstract]

Schedule of Changes in Asset Retirement Obligations

Changes in the asset retirement obligations (in thousands) are as follows:


	December 31, 2023		December 31, 2022
Beginning balance	$	20,732	$	32,049
Accretion	2,057		1,498
Additions and revisions of estimates	7,957		(12,753)
Payments	(332)		(62)
Ending balance	$	30,414	$	20,732

Accounts Receivable (Tables)

12 Months Ended

Dec. 31, 2023

Receivables [Abstract]

Schedule of Accounts Receivable and Allowance for Doubtful Accounts

Accounts receivable (in thousands) consisted of the following:


	December 31, 2023		December 31, 2022
Trade receivables	$	190,189	$	209,683
Less: Allowance for credit losses	(5,323)		(5,691)
Net trade receivables	184,866		203,992
Other receivables	1,051		4,639
Total accounts receivable	$	185,917	$	208,631

The following table reflects the change of the allowance for credit losses (in thousands) disaggregated by portfolio segments:


	Oil & Gas Proppants		Industrial & Specialty Products		Total
Beginning balance, December 31, 2022	$	4,028	$	1,663	$	5,691
Allowance for credit losses	—		(103)		(103)
Recoveries	95		—		95
Write-offs	(300)		(60)		(360)
Ending balance, December 31, 2023	$	3,823	$	1,500	$	5,323

Revenue - Foreign Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Total sales	$ 1,552,022	$ 1,525,147	$ 1,103,879
Pre-tax income	195,569	103,999	(37,076)
Net income	146,925	78,176	(33,761)
Foreign Operations
Disaggregation of Revenue [Line Items]
Total sales	110,107	112,753	96,317
Pre-tax income	23,355	16,313	11,252
Net income	$ 18,450	$ 12,887	$ 8,889

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References + Details

- Definition

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
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-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

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Asset Retirement Obligations - Schedule of Changes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	$ 20,732	$ 32,049
Accretion	2,057	1,498
Additions and revisions of estimates	7,957	(12,753)
Payments	(332)	(62)
Ending balance	$ 30,414	$ 20,732

Commitments and Contingencies - Future Minimum Annual Commitments (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Minimum Purchase Commitments
2024	$ 10,124
2025	6,815
2025	4,687
2026	2,288
2027	1,888
Thereafter	5,884
Total future purchase commitments	$ 31,686

Segment Reporting - Sales and Segment Contribution Margin for Reporting Segments and Other Operating Results (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information
Total sales	$ 1,552,022	$ 1,525,147	$ 1,103,879
Total segment contribution margin	549,663	472,117	328,551
Operating activities excluded from segment cost of sales	(18,268)	(17,159)	(19,655)
Selling, general and administrative	(118,797)	(143,838)	(119,628)
Depreciation, depletion and amortization	(137,259)	(140,166)	(161,131)
Goodwill and other asset impairments	0	0	(202)
Interest expense	(101,709)	(77,598)	(71,157)
Other income, net, including interest income	21,939	10,643	6,146
Income tax (expense) benefit	(49,080)	(26,159)	2,755
Net income (loss)	146,489	77,840	(34,321)
Less: Net loss attributable to non-controlling interest	(436)	(336)	(560)
Net income (loss) attributable to U.S. Silica Holdings, Inc.	146,925	78,176	(33,761)
Oil & Gas Proppants
Segment Reporting Information
Total sales	994,276	961,667	615,448
Total segment contribution margin	361,998	301,837	160,052
Industrial & Specialty Products
Segment Reporting Information
Total sales	557,746	563,480	488,431
Total segment contribution margin	$ 187,665	$ 170,280	$ 168,499

Property, Plant and Mine Development - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment
Depreciation, depletion and amortization	$ 137,259	$ 140,166	$ 161,131
Property, Plant and Mine Development
Property, Plant and Equipment
Depreciation, depletion and amortization	$ 124,900	$ 128,400

Earnings Per Share

12 Months Ended

Dec. 31, 2023

Earnings Per Share [Abstract]

EARNINGS PER SHARE

NOTE C—EARNINGS PER SHARE

Basic earnings per common share is computed by dividing income available to common stockholders by the weighted average number of common shares outstanding for the period. Diluted earnings per common share is computed similarly to basic earnings per common share except that the weighted average number of common shares outstanding is increased to include the number of additional common shares that would have been outstanding if the potentially dilutive common shares had been issued.

The following table shows the computation of basic and diluted earnings per share:


In thousands, except per share amounts	Year ended December 31,
	2023		2022		2021
Numerator:
Net income (loss) attributable to U.S. Silica Holdings, Inc.	$	146,925	$	78,176	$	(33,761)

Denominator:
Weighted average shares outstanding	76,980		75,512		74,350
Diluted effect of stock awards	1,540		2,158		—
Weighted average shares outstanding assuming dilution	78,520		77,670		74,350

Earnings (loss) per share attributable to U.S. Silica Holdings, Inc.:
Basic earnings (loss) per share	$	1.91	$	1.04	$	(0.45)
Diluted earnings (loss) per share	$	1.87	$	1.01	$	(0.45)

Potentially dilutive shares are excluded from the calculation of diluted weighted average shares outstanding and diluted earnings per share if we are in a loss position. Certain stock options, restricted stock awards and performance share units were excluded from the computation of diluted earnings per share because their effect would have been anti-dilutive. Such potentially dilutive shares and stock awards (in thousands) excluded from the calculation of diluted earnings (loss) per common share were as follows:


	Year ended December 31,
	2023	2022	2021
Potentially dilutive shares excluded	—	—	1,714
Stock options excluded	349	509	667
Restricted stock and performance share units awards excluded	48	36	66

Leases - Maturities of Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Operating leases
2024	$ 23,405
2025	17,252
2026	13,172
2027	9,413
2028	7,171
Thereafter	21,727
Total lease payments	92,140
Less: Interest	16,714
Less: Other operating expenses	1,768
Total	73,658
Finance leases
2024	1,342
2025	1,060
2026	896
2027	46
2028	46
Thereafter	144
Total lease payments	3,534
Less: Interest	426
Less: Other operating expenses	0
Total	$ 3,108	$ 3,260

Pension and Post-Retirement Benefits - Estimated Future Pension and Post-Retirement Benefit Payments (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Pension Benefits
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2024	$ 7,159
2025	7,117
2026	7,145
2027	7,051
2028	6,966
2029-2033	32,951
Post-retirement Benefits \| Before Medicare Subsidy
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2024	864
2025	776
2026	711
2027	659
2028	596
2029-2033	2,400
Post-retirement Benefits \| After Medicare Subsidy
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2024	864
2025	776
2026	711
2027	659
2028	596
2029-2033	$ 2,400

Asset Retirement Obligations

12 Months Ended

Dec. 31, 2023

Asset Retirement Obligation Disclosure [Abstract]

ASSET RETIREMENT OBLIGATIONS

NOTE K—ASSET RETIREMENT OBLIGATIONS

Mine reclamation or future remediation costs for inactive mines are accrued based on management’s best estimate at the end of each period of the costs expected to be incurred at a site. Such cost estimates include, where applicable, ongoing care, maintenance and monitoring costs. Changes in estimates at inactive mines are reflected in earnings in the period an estimate is revised. Liabilities related to our asset retirement obligations are recorded in other long-term liabilities on our balance sheets. Changes in the asset retirement obligations (in thousands) are as follows:


	December 31, 2023		December 31, 2022
Beginning balance	$	20,732	$	32,049
Accretion	2,057		1,498
Additions and revisions of estimates	7,957		(12,753)
Payments	(332)		(62)
Ending balance	$	30,414	$	20,732

The increase in liability is primarily attributable to revisions of estimates of reclamation costs and changes to lives of mines.

Income Taxes - Effective Income Tax Rate on Pretax Earnings (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income tax (expense) benefit computed at U.S. federal statutory rate	$ (41,069)	$ (21,838)	$ 7,786
Decrease (increase) resulting from:
Statutory depletion	3,758	2,963	2,012
Prior year tax return reconciliation	(996)	(1,564)	(2,490)
State income taxes, net of federal benefit	(7,385)	(4,003)	445
Impact of international operations	(854)	(830)	(380)
Unrecognized tax benefits	1,055	(89)	(1,302)
Equity compensation	1,684	(195)	(627)
Executive compensation	(4,963)	(300)	(2,092)
Other, net	(310)	(303)	(597)
Income tax (expense) benefit	$ (49,080)	$ (26,159)	$ 2,755

Derivative Instruments

12 Months Ended

Dec. 31, 2023

Derivative Instruments and Hedging Activities Disclosure [Abstract]

DERIVATIVE INSTRUMENTS

NOTE M—DERIVATIVE INSTRUMENTS

Cash Flow Hedges of Natural Gas Price Risk

Natural gas is the primary fuel source used for drying in the commercial silica production process. In the past, the price of natural gas has been volatile, and we believe this volatility may continue. In order to manage our exposure to natural gas price increases, we have entered into natural gas swaps. All of these swap agreements commenced in December 2022. The derivative instruments are recorded on the balance sheet within other current or long-term assets or liabilities based on maturity dates at their fair values. As of December 31, 2023, the fair value of our natural gas swaps was a liability of $1.9 million, of which $1.8 million is classified within accounts payable and accrued liabilities on our balance sheet and $0.1 million is classified within other long-term obligations on our balance sheet. As of December 31, 2022, the fair value of our natural gas swaps was a liability of $3.1 million, of which $2.3 million is classified within accounts payable and accrued liabilities on our balance sheet and $0.8 million is classified within other long-term obligations on our balance sheet.

We have designated the natural gas swap agreements as qualified cash flow hedges. Accordingly, the effective portion of the gain or loss on the derivative instrument is reported as a component of other comprehensive income and recognized in earnings in the same period or periods during which the hedged transaction affects earnings.


	December 31, 2023						December 31, 2022
	Maturity Date	Contract/Notional Amount (MMBtu)	Carrying Amount		Fair Value		Maturity Date	Contract/Notional Amount	Carrying Amount		Fair Value
Natural Gas - W. Texas (WAHA) - Inside FERC	2023	1,200,000	$	—	$	—	2023	1,200,000	$	(1,887)	$	(1,887)
Natural Gas - W. Texas (WAHA) - Inside FERC	2024	870,000	$	(1,542)	$	(1,542)	2024	870,000	$	(656)	$	(656)
Natural Gas - W. Texas (WAHA) - Inside FERC	2024	750,000	$	(11)	$	(11)	N/A	N/A	$	—	$	—
Natural Gas - Henry Hub - NYMEX	2023	300,000	$	—	$	—	2023	300,000	$	(425)	$	(425)
Natural Gas - Henry Hub - NYMEX	2024	120,000	$	(258)	$	(258)	2024	120,000	$	(85)	$	(85)
Natural Gas - Henry Hub - NYMEX	2025	90,000	$	(115)	$	(115)	2025	90,000	$	(35)	$	(35)

During the year ended December 31, 2023, we had no ineffectiveness for the natural gas swap derivatives.

The following table summarizes the effect of derivative instruments (in thousands) on our income statements and our consolidated statements of comprehensive income:


	Year ended December 31,
	2023		2022		2021
Deferred losses from derivatives in OCI, beginning of period	$	(2,342)	$	—	$	—
Gain (loss) recognized in OCI from derivative instruments	882		(2,342)		—

Deferred losses from derivatives in OCI, end of period	$	(1,460)	$	(2,342)	$	—

Pension and Post-Retirement Benefits - Fair Value of Pension Plan Assets, by Asset Category (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	$ 67,064	$ 88,919
Cash and cash equivalents
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	1,652	1,362
Diversified emerging markets
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	2,960	4,221
Foreign large blend
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	11,707	16,740
Large-cap blend
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	11,685	15,464
Mid-cap blend
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	6,763	7,720
Real assets
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	3,204	4,144
Corporate notes and bonds
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	17,768	27,892
U.S. Treasuries
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	5,012	5,223
Mortgage-backed securities
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	3,250	3,000
Asset-backed securities
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	3,063	3,153
Level 1
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	59,099	81,404
Level 1 \| Cash and cash equivalents
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	0	0
Level 1 \| Diversified emerging markets
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	2,960	4,221
Level 1 \| Foreign large blend
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	11,707	16,740
Level 1 \| Large-cap blend
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	11,685	15,464
Level 1 \| Mid-cap blend
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	6,763	7,720
Level 1 \| Real assets
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	3,204	4,144
Level 1 \| Corporate notes and bonds
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	17,768	27,892
Level 1 \| U.S. Treasuries
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	5,012	5,223
Level 1 \| Mortgage-backed securities
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	0	0
Level 1 \| Asset-backed securities
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	0	0
Level 2
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	7,965	7,515
Level 2 \| Cash and cash equivalents
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	1,652	1,362
Level 2 \| Diversified emerging markets
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	0	0
Level 2 \| Foreign large blend
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	0	0
Level 2 \| Large-cap blend
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	0	0
Level 2 \| Mid-cap blend
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	0	0
Level 2 \| Real assets
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	0	0
Level 2 \| Corporate notes and bonds
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	0	0
Level 2 \| U.S. Treasuries
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	0	0
Level 2 \| Mortgage-backed securities
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	3,250	3,000
Level 2 \| Asset-backed securities
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	3,063	3,153
Level 3
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	0	0
Level 3 \| Cash and cash equivalents
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	0	0
Level 3 \| Diversified emerging markets
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	0	0
Level 3 \| Foreign large blend
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	0	0
Level 3 \| Large-cap blend
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	0	0
Level 3 \| Mid-cap blend
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	0	0
Level 3 \| Real assets
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	0	0
Level 3 \| Corporate notes and bonds
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	0	0
Level 3 \| U.S. Treasuries
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	0	0
Level 3 \| Mortgage-backed securities
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	0	0
Level 3 \| Asset-backed securities
Pension Plans, Postretirement and Other Employee Benefits
Fair value of pension plan assets	$ 0	$ 0

Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Line of Credit Facility
Less: Unamortized original issue discount	$ (24,183)	$ (2,035)
Less: Unamortized debt issuance cost	(13,421)	(8,922)
Finance leases	3,108	3,260
Total debt	840,037	1,056,993
Less: current portion	(16,367)	(19,535)
Total long-term portion of debt	823,670	1,037,458
Notes Payable \| Insurance financing notes payable
Line of Credit Facility
Insurance financing notes payable	$ 6,470	$ 5,628
Revolving Credit Facility \| Revolver expiring March 23, 2028 (10.21% at December 31, 2023 and 8.44% at December 31, 2022)
Line of Credit Facility
Credit facility, interest rate	10.21%	8.44%
Long-term debt	$ 0	$ 0
Senior Secured Credit Facility \| Term Loan facility—final maturity March 23, 2030 (10.21% at December 31, 2023 and 8.44% December 31, 2022)
Line of Credit Facility
Credit facility, interest rate	10.21%	8.44%
Long-term debt	$ 868,063	$ 1,059,062

Derivative Instruments - Effect of Derivatives Instruments on Combined Statements of Operations and Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance	$ 704,694	$ 614,083	$ 626,791
Gain (loss) recognized in OCI from derivative instruments	2,352
Ending Balance	855,527	704,694	614,083
Unrealized loss on cash flow hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance	(2,342)	0	0
Gain (loss) recognized in OCI from derivative instruments	882	(2,342)	0
Ending Balance	$ (1,460)	$ (2,342)	$ 0

- Definition

Amount of equity (deficit) attributable to parent and noncontrolling interest. Excludes temporary equity.

+ References

+ Details

Accounts Payable and Accrued Liabilities (Tables)

12 Months Ended

Dec. 31, 2023

Payables and Accruals [Abstract]

Schedule of Accounts Payables and Accrued Liabilities

Accounts payable and accrued liabilities (in thousands) consisted of the following:


	December 31,
	2023		2022
Trade payables	$	123,667	$	182,555
Accrued salaries and wages	7,013		10,911
Accrued vacation liability	3,567		3,093
Current portion of liability for pension and post-retirement benefits	986		1,118
Accrued healthcare liability	1,571		1,492
Accrued property taxes and sales taxes	3,422		4,287

Current portion of derivative liability	1,819		2,312
Other accrued liabilities	5,434		10,471
Accounts payable and accrued liabilities	$	147,479	$	216,239

Organization	12 Months Ended
Organization	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
ORGANIZATION	NOTE A—ORGANIZATION U.S. Silica Holdings, Inc. (“Holdings,” and together with its subsidiaries “we,” “us” or the “Company”) is a global performance materials company and a leading producer of commercial silica used in the oil and gas industry and in a wide range of industrial applications. In addition, through our subsidiary EP Minerals, LLC ("EPM") we are an industry leader in the production of industrial minerals, including diatomaceous earth, clay (calcium bentonite and calcium montmorillonite) and perlite. During our 124-year history, we have developed core competencies in mining, processing, logistics and materials science that enable us to produce and cost-effectively deliver products to customers across our end markets. Our operations are organized into two reportable segments based on end markets served: (1) Oil & Gas Proppants and (2) Industrial & Specialty Products. See Note U - Segment Reporting for more information on our reportable segments.

Revenue (Tables)

12 Months Ended

Dec. 31, 2023

Revenue from Contract with Customer [Abstract]

Schedule of Sales by Major Source

The following table reflects our sales disaggregated by major source (in thousands):


	Year Ended December 31, 2023						Year Ended December 31, 2022
Category	Oil & Gas Proppants		Industrial & Specialty Products		Total Sales		Oil & Gas Proppants		Industrial & Specialty Products		Total Sales
Product	$	673,848	$	557,746	$	1,231,594	$	576,293	$	563,480	$	1,139,773
Service	320,428		—		320,428		385,374		—		385,374
Total Sales	$	994,276	$	557,746	$	1,552,022	$	961,667	$	563,480	$	1,525,147

Schedule of Changes in Contract Assets and Liabilities

The following tables reflect the changes in our contract assets, which we classify as unbilled receivables and our contract liabilities, which we classify as deferred revenues (in thousands):


	Unbilled Receivables
	December 31, 2023		December 31, 2022
Beginning Balance	$	—	$	1,957
Reclassifications to billed receivables	—		(4,457)
Revenues recognized in excess of period billings	—		2,500
Ending Balance	$	—	$	—


	Deferred Revenue
	December 31, 2023		December 31, 2022
Beginning Balance	$	30,752	$	20,741
Revenues recognized from balances held at the beginning of the period	(15,370)		(3,905)
Revenues deferred from period collections on unfulfilled performance obligations	130		27,398
Revenues recognized from period collections	—		(13,482)
Ending Balance	$	15,512	$	30,752

Schedule of Information Related to Foreign Operations

The following table includes information related to our foreign operations (in thousands):


	For the years ended
	December 31, 2023		December 31, 2022		December 31, 2021
Total Sales	$	110,107	$	112,753	$	96,317
Pre-tax income	$	23,355	$	16,313	$	11,252
Net income	$	18,450	$	12,887	$	8,889

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pay vs Performance Disclosure
Net Income (Loss)	$ 146,925	$ 78,176	$ (33,761)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

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+ Details

Accounts Receivable (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Receivables [Abstract]
Trade receivables	$ 190,189	$ 209,683
Less: Allowance for credit losses	(5,323)	(5,691)
Net trade receivables	184,866	203,992
Other receivables	1,051	4,639
Total accounts receivable	$ 185,917	$ 208,631

Parent Company Financials - Condensed Statements of Cash Flows (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Condensed Cash Flow Statements, Captions [Line Items]
Net income	$ 146,489,000	$ 77,840,000	$ (34,321,000)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Accounts payable and accrued liabilities	(65,916,000)	67,576,000	48,709,000
Net cash provided by operating activities	263,868,000	262,716,000	169,347,000
Investing activities:
Net cash used in investing activities	(44,721,000)	(50,953,000)	(29,856,000)
Financing activities:
Dividends paid	(23,000)	(164,000)	(26,000)
Proceeds from options exercised	0	955,000	105,000
Tax payments related to shares withheld for vested restricted stock and stock units	(10,549,000)	(2,953,000)	(5,023,000)
Net cash used in financing activities	(254,276,000)	(170,343,000)	(50,986,000)
Cash and cash equivalents, beginning of period	280,845,000	239,425,000	150,920,000
Cash and cash equivalents, end of period	245,716,000	280,845,000	239,425,000
Cash received during the period for:
Interest	(95,133,000)	(71,235,000)	(64,650,000)
Cash dividends paid to the parent by its consolidated entities	0	0	0
Parent Company
Condensed Cash Flow Statements, Captions [Line Items]
Net income	146,489,000	77,840,000	(34,321,000)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Undistributed (income) loss from equity method investment, net	(143,758,000)	(77,528,000)	34,074,000
Other receivables	275,000	(275,000)	0
Accounts payable and accrued liabilities	0	0	(236,000)
Net cash provided by operating activities	3,006,000	37,000	(483,000)
Investing activities:
Investment in subsidiary	0	0	0
Net cash used in investing activities	0	0	0
Financing activities:
Dividends paid	(23,000)	(164,000)	(26,000)
Proceeds from options exercised	0	955,000	105,000
Tax payments related to shares withheld for vested restricted stock and stock units	(10,549,000)	(2,953,000)	(5,023,000)
Distributions to non-controlling interest	(1,354,000)	(1,523,000)	(1,103,000)
Net financing activities with subsidiaries	61,900,000	5,050,000	6,675,000
Net cash used in financing activities	49,974,000	1,365,000	628,000
Net increase in cash and cash equivalents	52,980,000	1,402,000	145,000
Cash and cash equivalents, beginning of period	48,398,000	46,996,000	46,851,000
Cash and cash equivalents, end of period	101,378,000	48,398,000	46,996,000
Cash received during the period for:
Interest	$ (2,983,000)	$ (565,000)	$ (17,000)

Pension and Post-Retirement Benefits - Changes in Benefit Obligations and Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Plan Assets
Fair value of plan assets at January 1,	$ 88,919
Fair value of plan assets at December 31,	67,064	$ 88,919
Pension Benefits
Benefit Obligation
Benefit obligation at January 1,	112,247	144,251
Service cost	2,325	2,516	$ 2,855
Interest cost	5,343	3,120	2,619
Actuarial loss (gain)	2	(28,494)
Benefits paid	(31,352)	(9,486)
Other	74	340
Benefit obligation at December 31,	88,639	112,247	144,251
Plan Assets
Fair value of plan assets at January 1,	88,919	120,911
Actual return on plan assets	7,497	(22,507)
Employer contributions	2,000	0
Benefits paid	(31,352)	(9,486)
Other	0	1
Fair value of plan assets at December 31,	67,064	88,919	120,911
Plan assets less than benefit obligations at December 31 recognized as liability for pension and other post-retirement benefits	(21,575)	(23,328)
Post-retirement Benefits
Benefit Obligation
Benefit obligation at January 1,	7,577	9,391
Service cost	8	18	24
Interest cost	332	180	141
Actuarial loss (gain)	(552)	(1,566)
Benefits paid	(469)	(504)
Other	34	58
Benefit obligation at December 31,	6,930	7,577	9,391
Plan Assets
Fair value of plan assets at January 1,	0	0
Actual return on plan assets	0	0
Employer contributions	435	446
Benefits paid	(469)	(504)
Other	34	58
Fair value of plan assets at December 31,	0	0	$ 0
Plan assets less than benefit obligations at December 31 recognized as liability for pension and other post-retirement benefits	$ (6,930)	$ (7,577)

Debt

12 Months Ended

Dec. 31, 2023

Debt Disclosure [Abstract]

DEBT

NOTE J—DEBT

Debt (in thousands) consisted of the following:


	December 31, 2023		December 31, 2022
Senior secured credit facility:
Revolver expiring March 23, 2028 (10.21% at December 31, 2023 and 8.44% at December 31, 2022)	$	—	$	—
Term Loan facility—final maturity March 23, 2030 (10.21% at December 31, 2023 and 8.44% December 31, 2022)	868,063		1,059,062
Less: Unamortized original issue discount	(24,183)		(2,035)
Less: Unamortized debt issuance cost	(13,421)		(8,922)
Insurance financing notes payable	6,470		5,628
Finance leases	3,108		3,260
Total debt	840,037		1,056,993
Less: current portion	(16,367)		(19,535)
Total long-term portion of debt	$	823,670	$	1,037,458

Senior Secured Credit Facility

On March 23, 2023, we entered into a Fourth Amended and Restated Credit Agreement (the "Credit Agreement"), by entering into a new $1.1 billion senior secured Credit Facility, consisting of a $950 million Term Loan (the "Term Loan") and a $150 million revolving credit facility (the "Revolver") (collectively the "Credit Facility") that may also be used for swingline loans or letters of credit, and we may elect to increase the term loan or the revolving credit facility in accordance with the terms of the Credit Agreement. Borrowings under the Credit Agreement will bear interest at variable rates as determined at our election, based on the Term Secured Overnight Financing Rate ("SOFR") or a base rate, in each case, plus an applicable margin. In addition, under the Credit Agreement, we are required to pay a per annum commitment fee to revolving lenders and fees for letters of credit. The Credit Agreement is secured by substantially all of our assets and our domestic subsidiaries' assets and a pledge of the equity interests in such entities. The Term Loan matures on March 23, 2030, and the Revolver expires March 23, 2028. We capitalized $45.9 million in debt issuance costs and original issue discount as a result of the new Credit Agreement. Additionally, as a result of the exit of certain lending parties, a portion of debt issuance and original discount costs were written off which resulted in additional expense of approximately $4.3 million. This was recorded as a loss on the extinguishment of debt, which was recorded in Other (expense) income, net, including interest income in the Consolidated Statements of Operations.

The Credit Facility contains covenants that, among other things, limit our ability, and certain of our subsidiaries' abilities, to create, incur or assume indebtedness and liens, to make acquisitions or investments, to sell assets and to pay dividends. The Credit Agreement also requires us to maintain a consolidated leverage ratio of no more than 4.00:1.00 as of the last day of any fiscal quarter whenever usage of the Revolver (other than certain undrawn letters of credit) exceeds 35%, of the Revolver commitment. These covenants are subject to a number of important exceptions and qualifications. The Credit Agreement includes events of default and other affirmative and negative covenants that are usual for facilities and transactions of this type. As of December 31, 2023 and 2022, we were in compliance with all covenants in accordance with our senior secured Credit Facility.

Term Loan

At December 31, 2023, contractual maturities of our senior secured Credit Facility (in thousands) are as follows:


2024	$	8,750
2025	8,750
2026	8,750
2027	8,750
2028	8,750
Thereafter	824,313
Total	$	868,063

Debt Repurchases

Prior to the execution of the Fourth Amended and Restated Credit Agreement, we repurchased outstanding debt under the Term Loan in the amount of $109 million. A proportionate share of debt issuance and original discount costs were written off in conjunction with this repurchase which resulted in additional expense of approximately $1.0 million. As a result, we recorded a loss on extinguishment of debt in the amount of $1.0 million. The loss on extinguishment was recorded in Other (expense) income, net, including interest income in the Consolidated Statements of Operations.

During the year ended December 31, 2023, we made voluntary prepayments on the Term Loan of $75 million. A proportionate share of debt issuance and original discount costs were written off in conjunction with the prepayments of this debt which resulted in additional expense of $3.2 million. These expenses were recorded in Other (expense) income, net, including interest income in the Consolidated Statements of Operations.

During the year ended December 31, 2022, we repurchased outstanding debt under the Term Loan in the amounts of $100 million and $50 million, discounted at rates of 97% and 96.25%, respectively. A proportionate share of debt issuance and original discount costs were written off in conjunction with these repurchases which resulted in additional expense of approximately $1.8 million. As a result, we recorded gains on extinguishment of debt in the amount of approximately $2.9 million. The gains on extinguishment were recorded in Other income, net, including interest income in the Consolidated Statements of Operations.

Revolving Line-of-Credit

We have a $150.0 million Revolver with zero drawn and $15.3 million allocated for letters of credit as of December 31, 2023, leaving $134.7 million available under the Revolver.

Based on our consolidated leverage ratio of 1.91:1.00 as of December 31, 2023, we have access to the full availability of the Revolver.

Insurance Financing Notes Payable

During the third quarter of 2023, we renewed our insurance policies and financed the payments through notes payable with a stated interest rate of 6.6%. These payments will be made in installments throughout a nine-month period and, as such, were classified as current debt. As of December 31, 2023, the notes payable had a balance of $6.5 million.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(c))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 470
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//470/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1E
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1E

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

+ Details

Parent Company Financials - Condensed Statements of Operations and Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Condensed Income Statements, Captions [Line Items]
Total sales	$ 1,552,022	$ 1,525,147	$ 1,103,879
Cost of sales	1,020,627	1,070,189	794,983
Operating expenses:
Selling, general and administrative	118,797	143,838	119,628
Total operating expenses	256,056	284,004	280,961
Operating income	275,339	170,954	27,935
Other income (expense)
Total other expense	(79,770)	(66,955)	(65,011)
Income tax benefit (expense)	(49,080)	(26,159)	2,755
Net income (loss)	146,489	77,840	(34,321)
Less: Net loss attributable to non-controlling interest	(436)	(336)	(560)
Net income (loss) attributable to U.S. Silica Holdings, Inc.	146,925	78,176	(33,761)
Other comprehensive income (loss)
Unrealized gain (loss) on derivatives (net of tax of $281, $(746), and $0 for 2023, 2022, and 2021, respectively)	882	(2,342)	0
Foreign currency translation adjustment (net of tax of $90, $(269), and $(309) for 2023, 2022 and 2021, respectively)	281	(845)	(1,000)
Pension and other post-retirement benefits liability adjustments (net of tax of $139, $355, and $3,131 for 2023, 2022 and 2021, respectively)	435	1,115	9,828
Comprehensive income (loss)	148,087	75,768	(25,493)
Less: Comprehensive loss attributable to non-controlling interest	(436)	(336)	(560)
Comprehensive income (loss) attributable to U.S. Silica Holdings, Inc.	148,523	76,104	(24,933)
Tax expense (benefit) on unrealized gain (loss) on derivatives	281	(746)	0
Tax expense (benefit) on foreign currency translation adjustment	90	(269)	(309)
Tax (expense) benefit on pension and other post-retirement benefits liability adjustment	139	355	3,131
Parent Company
Condensed Income Statements, Captions [Line Items]
Total sales	0	0	0
Cost of sales	0	0	0
Operating expenses:
Selling, general and administrative	252	253	252
Total operating expenses	252	253	252
Operating income	(252)	(253)	(252)
Other income (expense)
Interest income	2,983	565	5
Total other expense	2,983	565	5
Income (loss) before income taxes and equity in net earnings of subsidiaries	2,731	312	(247)
Income tax benefit (expense)	0	0	0
Income (loss) before equity in net earnings of subsidiaries	2,731	312	(247)
Equity in earnings of subsidiaries, net of tax	143,758	77,528	(34,074)
Net income (loss)	146,489	77,840	(34,321)
Less: Net loss attributable to non-controlling interest	(436)	(336)	(560)
Net income (loss) attributable to U.S. Silica Holdings, Inc.	146,925	78,176	(33,761)
Other comprehensive income (loss)
Unrealized gain (loss) on derivatives (net of tax of $281, $(746), and $0 for 2023, 2022, and 2021, respectively)	882	(2,342)	0
Foreign currency translation adjustment (net of tax of $90, $(269), and $(309) for 2023, 2022 and 2021, respectively)	281	(845)	(1,000)
Pension and other post-retirement benefits liability adjustments (net of tax of $139, $355, and $3,131 for 2023, 2022 and 2021, respectively)	435	1,115	9,828
Comprehensive income (loss)	148,087	75,768	(25,493)
Less: Comprehensive loss attributable to non-controlling interest	(436)	(336)	(560)
Comprehensive income (loss) attributable to U.S. Silica Holdings, Inc.	148,523	76,104	(24,933)
Tax expense (benefit) on unrealized gain (loss) on derivatives	281	(746)	0
Tax expense (benefit) on foreign currency translation adjustment	90	(269)	(309)
Tax (expense) benefit on pension and other post-retirement benefits liability adjustment	$ 139	$ 355	$ 3,131

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2023
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	NOTE W— SUBSEQUENT EVENTS We evaluated subsequent events through the date the consolidated financial statements were available for issuance and did not identify any events requiring disclosure.