U.S. Silica (SLCA) 10-Q 28 Oct 15 2015 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2015	Oct. 26, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q3
Entity Registrant Name	U.S. Silica Holdings, Inc.
Entity Central Index Key	1,524,741
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		53,384,160

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Current Assets:
Cash and cash equivalents	$ 253,765	$ 267,281
Short-term investments	46,007	75,143
Accounts receivable, net	85,605	120,881
Inventories, net	70,671	66,712
Prepaid expenses and other current assets	12,516	9,267
Deferred income taxes, net	8,925	22,295
Income tax deposits	6,260	746
Total current assets	483,749	562,325
Property, plant and mine development, net	563,262	565,755
Goodwill	68,647	68,647
Trade names	14,914	14,914
Customer relationships, net	6,577	6,984
Other assets	19,444	12,317
Total assets	1,156,593	1,230,942
Current Liabilities:
Book overdraft	2,405	4,215
Accounts payable	57,982	85,781
Dividends payable	6,772	6,805
Accrued liabilities	14,055	17,911
Accrued interest	58	60
Current portion of long-term debt	3,327	3,329
Deferred revenue	14,022	26,771
Total current liabilities	98,621	144,872
Long-term debt	489,208	491,757
Deferred revenue	64,759	64,722
Liability for pension and other post-retirement benefits	60,099	59,932
Deferred income taxes, net	28,124	49,749
Other long-term obligations	18,115	16,094
Total liabilities	758,926	827,126
Stockholders’ Equity:
Common stock	539	539
Additional paid-in capital	192,915	191,086
Retained earnings	239,655	232,551
Treasury stock, at cost	(15,960)	(542)
Accumulated other comprehensive loss	(19,482)	(19,818)
Total stockholders’ equity	397,667	403,816
Total liabilities and stockholders’ equity	$ 1,156,593	$ 1,230,942

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Statement [Abstract]
Sales	$ 155,408	$ 241,256	$ 506,877	$ 627,152
Cost of goods sold (excluding depreciation, depletion and amortization)	122,599	149,697	378,452	408,884
Operating expenses
Selling, general and administrative	13,559	18,600	47,095	53,312
Depreciation, depletion and amortization	15,158	12,425	42,096	32,355
Total operating expenses	28,717	31,025	89,191	85,667
Operating income	4,092	60,534	39,234	132,601
Other income/(expense)
Interest expense	(6,684)	(4,950)	(20,448)	(12,771)
Other income, net, including interest income	309	120	818	379
Total other (expenses) income	(6,375)	(4,830)	(19,630)	(12,392)
Income/(loss) before income taxes	(2,283)	55,704	19,604	120,209
Income tax benefit/(expense)	4,695	(14,427)	7,584	(31,907)
Net income	$ 2,412	$ 41,277	$ 27,188	$ 88,302
Earnings per share:
Basic (in usd per share)	$ 0.05	$ 0.77	$ 0.51	$ 1.64
Diluted (in usd per share)	$ 0.04	$ 0.76	$ 0.51	$ 1.63
Weighted Average Number of Shares Outstanding, Basic	53,321	53,801	53,386	53,679
Weighted Average Number of Shares Outstanding, Diluted	53,742	54,393	53,831	54,265
Common stock cash dividend declared, per share	$ 0.13	$ 0.13	$ 0.375	$ 0.38

Condensed Consolidated Stateme4

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 2,412	$ 41,277	$ 27,188	$ 88,302
Other comprehensive income/(loss):
Unrealized gain (loss) on derivatives (net of tax of $10 and $1 for the three months ended September 30, 2015 and 2014, respectively, and $18 and ($33) for the nine months ended September 30, 2015 and 2014, respectively)	17	1	29	(52)
Unrealized gain on investments (net of tax of $3 and $2 for the three months ended September 30, 2015 and 2014, respectively, and $33 and $16 for the nine months ended September 30, 2015 and 2014, respectively)	4	2	53	25
Pension and other post-retirement benefits liability adjustment (net of tax of ($2,431) and $95 for the three months ended September 30, 2015 and 2014, respectively, and $157 and $285 for the nine months ended September 30, 2015 and 2014, respectively)	(3,924)	149	254	447
Comprehensive income/(loss)	$ (1,491)	$ 41,429	$ 27,524	$ 88,722

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Unrealized gain (loss) on derivatives, tax	$ 10	$ 1	$ 18	$ (33)
Unrealized gain (loss) on investments, tax	3	2	33	16
Pension and other post-retirement benefits liability adjustment, tax	$ (2,431)	$ 95	$ 157	$ 285

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Stockholders' Equity - 9 months ended Sep. 30, 2015 - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-In Capital	Retained Earnings (Deficit)	Accumulated Other Comprehensive Income (Loss)
Balance at December 31, 2014 at Dec. 31, 2014	$ 403,816	$ 539	$ (542)	$ 191,086	$ 232,551	$ (19,818)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	27,188				27,188
Unrealized gain on derivatives	29					29
Unrealized gain on short-term investments	53					53
Pension and post-retirement liability	254					254
Cash dividend declared ($0.375 per share)	(20,084)				(20,084)
Common stock-based compensation plans activity:	1,824			1,824
Equity-based compensation	225			225
Unrealized gain on short-term investments	364		583	(219)
Pension and post-retirement liability	(747)	0	(746)	(1)
Repurchase of common stock	(15,255)		(15,255)
Balance at September 30, 2015 at Sep. 30, 2015	$ 397,667	$ 539	$ (15,960)	$ 192,915	$ 239,655	$ (19,482)

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Stockholders' Equity [Abstract]
Common stock cash dividend declared, per share	$ 0.13	$ 0.13	$ 0.375	$ 0.38

Condensed Consolidated Stateme8

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Operating activities:
Net income	$ 27,188	$ 88,302
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	42,096	32,355
Debt issuance amortization	1,054	657
Original issue discount amortization	288	197
Deferred income taxes	(8,463)	4,043
Deferred revenue	(12,712)	(3,669)
Loss on disposal of property, plant and equipment	1,007	134
Equity-based compensation	1,824	4,807
Excess tax benefit from equity-based compensation	(225)	(3,673)
Other	(8,773)	3,433
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable	36,587	(49,664)
Inventories	(3,959)	2,104
Prepaid expenses and other current assets	(3,303)	(1,378)
Income taxes	(5,514)	(84)
Accounts payable and accrued liabilities	(31,655)	32,214
Accrued interest	(2)	(5)
Liability for pension and other post-retirement benefits	978	(2,786)
Net cash provided by operating activities	36,416	106,987
Investing activities:
Capital expenditures	(38,167)	(51,576)
Proceeds from sales and maturities of short-term investments	29,388	0
Acquisition of business, net of cash acquired	0	(98,317)
Proceeds from sale of property, plant and equipment	77	13
Net cash used in investing activities	(8,702)	(149,880)
Financing activities:
Dividends paid	(20,117)	(20,132)
Repurchase of common stock	(15,255)	0
Proceeds from options exercised	364	5,433
Excess tax benefit from equity-based compensation	225	3,673
Tax payments related to shares withheld for vested restricted stock	(747)	(572)
Advances from customers	0	100,000
Repayment of long-term debt	(3,826)	(2,812)
Change in book overdraft	(1,810)	887
Principal payments on capital lease obligations	0	(132)
Financing fees	(64)	0
Net cash provided by/(used in) financing activities	(41,230)	86,345
Net increase/(decrease) in cash and cash equivalents	(13,516)	43,452
Cash and cash equivalents, beginning of period	267,281	78,256
Cash and cash equivalents, end of period	253,765	121,708
Cash paid during the period for:
Interest	16,359	11,545
Taxes	$ 6,176	$ 28,204

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	NOTE A—SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation and Consolidation The accompanying Condensed Consolidated Financial Statements (the “Financial Statements”) of U.S. Silica Holdings, Inc. (“Holdings,” and together with its subsidiaries “we,” “us” or the “Company”) included in this Quarterly Report on Form 10-Q, have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X issued by the U.S. Securities and Exchange Commission (“SEC”). They do not contain certain information included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2014 ; therefore, the interim Condensed Consolidated Financial Statements should be read in conjunction with that Annual Report on Form 10-K. In the opinion of management, all adjustments necessary for a fair presentation of the Financial Statements have been included. Such adjustments are of a normal, recurring nature. We have reclassified certain immaterial amounts in the prior years’ assets section of the consolidated balance sheets and operating activities section of the consolidated statement of cash flows to conform to the current year presentation. These reclassifications had no effect on previously reported total assets and net cash flows from operations. In order to make this report easier to read, we refer throughout to (i) our Condensed Consolidated Balance Sheets as our “Balance Sheets,” (ii) our Condensed Consolidated Statements of Operations as our “Income Statements,” and (iii) our Condensed Consolidated Statements of Cash Flows as our “Cash Flows.” Unaudited Interim Financial Statements The accompanying Balance Sheet as of September 30, 2015 ; the Income Statements for the three and nine months ended September 30, 2015 and 2014 ; the Condensed Consolidated Statements of Comprehensive Income for the three and nine months ended September 30, 2015 and 2014 ; the Condensed Consolidated Statements of Stockholders' Equity for the nine months ended September 30, 2015 ; the Cash Flows for the nine months ended September 30, 2015 and 2014 ; and other information disclosed in the related notes are unaudited. The Balance Sheet as of December 31, 2014 was derived from our audited consolidated financial statements as included in our 2014 Annual Report. Use of Estimates and Assumptions The preparation of the Financial Statements requires us 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 Financial Statements and the reported amounts of revenues and expenses during the reporting period. The more significant areas requiring the use of management estimates and assumptions relate to 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 doubtful accounts; estimates of fair value for certain reporting units and asset impairments (including impairments of goodwill 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; reserves for contingencies and litigation; and the fair value and accounting treatment of financial instruments including derivative 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. Recently Issued Accounting Pronouncements In April 2015, the Financial Accounting Standards Board ("FASB") issued an Accounting Standards Update, Interest-Imputation of Interest, which simplifies presentation of debt issuance costs. The new standard requires that debt issuance costs be presented in the balance sheet as a direct deduction from the carrying amount of debt liability, consistent with debt discounts or premiums. The new standard will be effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within fiscal years beginning after December 15, 2016. Early adoption of the amendments in this Update is permitted for financial statements that have not been previously issued. We have elected to adopt the standard early and have presented debt issuance costs as a direct deduction from the carrying amount of debt on our Balance Sheets as of September 30, 2015 and December 31, 2014 . On July 22, 2015, the FASB issued Accounting Standards Update, Simplifying the Measurement of Inventory. The new standard requires an entity to measure most inventory at the lower of cost and net realizable value, thereby simplifying the current guidance under which an entity must measure inventory at the lower of cost or market. The new standard will not apply to inventories that are measured using either the last-in, first-out (LIFO) method or the retail inventory method. This Update is effective for public entities for financial statements issued for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years; early application is permitted. We are currently evaluating the effect that the new guidance will have on our financial statements and related disclosures.

Capital Structure and Accumulat

Capital Structure and Accumulated Comprehensive Income	9 Months Ended
	Sep. 30, 2015
Equity [Abstract]
Capital Structure and Accumulated Comprehensive Income	NOTE B—CAPITAL STRUCTURE AND ACCUMULATED COMPREHENSIVE INCOME Common Stock Our Amended and Restated Certificate of Incorporation authorizes up to 500,000,000 shares of common stock, par value of $0.01 . Subject to the rights of holders of any series of preferred stock, all of the voting power of the stockholders of Holdings shall be vested in the holders of the common stock. There were 53,386,174 shares of common stock issued and outstanding at September 30, 2015 . As of September 30, 2014 , there were 53,902,295 shares issued and outstanding. In 2015 , our Board of Directors declared quarterly cash dividends as follows: Dividends per Common Share Declaration Date Record Date Payable Date $ 0.125 February 12, 2015 March 16, 2015 April 3, 2015 $ 0.125 May 8, 2015 June 15, 2015 July 6, 2015 $ 0.125 July 24, 2015 September 15, 2015 October 2, 2015 All dividends were paid as scheduled. Any determination to pay dividends and other distributions in cash, stock, or property by Holdings in the future will be at the discretion of our Board of Directors and will be dependent on then-existing conditions, including our business conditions, our financial condition, results of operations, liquidity, capital requirements, contractual restrictions including restrictive covenants contained in our debt agreements, and other factors. Additionally, because we are a holding company, our ability to pay dividends on our common stock may be limited by restrictions on the ability of our subsidiaries to pay dividends or make distributions to us, including restrictions under the terms of the agreements governing our indebtedness. Preferred Stock Our Amended and Restated Certificate of Incorporation authorizes our Board of Directors to issue up to 10,000,000 shares, in the aggregate, of preferred stock, par value of $0.01 in one or more series, to fix the powers, preferences and other rights of such series, and any qualifications, limitations or restrictions thereof, including the dividend rate, conversion rights, voting rights, redemption rights and liquidation preference, and to fix the number of shares to be included in any such series, without any further vote or action by our stockholders. There are no shares of preferred stock issued or outstanding at September 30, 2015 . At present, we have no plans to issue any preferred stock. Employee Stock Awards We grant stock options, restricted stock, restricted stock units and performance share units to our employees and directors under the Amended and Restated U.S. Silica Holdings, Inc. 2011 Incentive Compensation Plan. The weighted-average stock options that are antidilutive and are therefore excluded from the calculation of our diluted earnings per common share are: Three Months Ended Nine Months Ended 2015 2014 2015 2014 Weighted-average outstanding stock options excluded 726 — 464 — Share Repurchase Program We are authorized by our Board of Directors to repurchase shares of our outstanding common stock from time to time on the open market or in privately negotiated transactions. As of September 30, 2015 , we are authorized to repurchase up to $50 million of our common stock through December 11, 2015. Stock repurchases, if any, will be funded using our available liquidity. The timing and amount of stock repurchases will depend on a variety of factors, including the market conditions as well as corporate and regulatory considerations. Under our share repurchase program, as of September 30, 2015 , we have repurchased 706,093 shares of our common stock at an average price of $23.83 and are authorized to repurchase up to an additional $33.2 million of our common stock. Accumulated Other Comprehensive Income Accumulated other comprehensive income (loss) consists of fair value adjustments associated with cash flow hedges and accumulated adjustments for net experience losses and prior service cost related to employee benefit plans. The following table presents the changes in accumulated other comprehensive income by component during the nine months ended September 30, 2015 : For the Nine Months Ended September 30, 2015 Unrealized gain/(loss) on cash flow hedges Unrealized gain/(loss) on short-term investments Pension and other post-retirement benefits liability Total Beginning Balance $ (134 ) $ (41 ) $ (19,643 ) $ (19,818 ) Other comprehensive income (loss) before reclassifications (3 ) 53 (1,127 ) (1,077 ) Amounts reclassed from accumulated other comprehensive income 32 — 1,381 1,413 Ending Balance $ (105 ) $ 12 $ (19,389 ) $ (19,482 ) Amounts reclassified from accumulated other comprehensive income (loss) related to cash flow hedges category are included in interest expense in our Income Statements and amounts reclassified related to pension and other post-retirement benefits liability category are included in the computation of net periodic pension costs, respectively, at before tax amounts.

Business Combination

Business Combination	9 Months Ended
	Sep. 30, 2015
Business Combinations [Abstract]
Business Combinations	NOTE C—BUSINESS COMBINATIONS On July 31, 2014, we completed our acquisition of Cadre Services, Inc. ("Cadre"), a regional sand mining company based in Voca, Texas, for approximately $98.3 million in cash. The acquisition of Cadre resulted in goodwill of approximately $0.2 million , none of which is deductible for tax purposes. This amount represents the residual amount of the total purchase price after allocation to the assets acquired and liabilities assumed. The table below represents the tangible and identifiable intangible assets and liabilities based on management’s assessment of the acquisition date fair value of the assets acquired and liabilities assumed: Accounts receivable $ 6,898 Inventory 2,534 Other current assets 174 Fixed assets 73,138 Deferred tax assets (net) 13,966 Accounts payable, accrued expenses and other liabilities (4,389 ) Net tangible assets acquired 92,321 Customer relationships 1,274 Trade name 4,478 Goodwill 244 Purchase price, net of cash acquired $ 98,317 The value of acquired intangible assets and the related estimated useful lives consist of the following: Estimated Useful Lives Value Customer relationships 15 years $ 1,274 Trade name Indefinite 4,478 Total intangible assets $ 5,752 Pro Forma Adjusted Summary The results of Cadre’s operations have been included in the consolidated financial statements subsequent to the acquisition date. The following unaudited pro forma consolidated financial information reflects the results of operations as if the Cadre acquisition had occurred on January 1, 2014, after giving effect to certain purchase accounting adjustments. This information does not purport to be indicative of the actual results that would have occurred if the acquisition had actually been completed on the date indicated, nor is it necessarily indicative of the future operating results or the financial position of the combined company: Three Months Ended Nine Months Ended Sales $ 245,625 $ 652,288 Net income 42,466 92,349 Basic earnings per share $ 0.79 $ 1.72 Diluted earnings per share 0.78 1.70

Accounts Receivable

Accounts Receivable	9 Months Ended
	Sep. 30, 2015
Receivables [Abstract]
Accounts Receivable	NOTE D—ACCOUNTS RECEIVABLE At September 30, 2015 and December 31, 2014 , accounts receivable consisted of the following: September 30, December 31, Trade receivables $ 93,404 $ 128,498 Less: Allowance for doubtful accounts (9,118 ) (10,429 ) Net trade receivables 84,286 118,069 Other receivables 1,319 2,812 Total accounts receivable $ 85,605 $ 120,881 Changes in our allowance for doubtful accounts during the nine months ended September 30, 2015 are as follows: September 30, Beginning balance $ 10,429 Bad debt provision (211 ) Write-offs (1,100 ) Ending balance $ 9,118

Inventories

Inventories	9 Months Ended
	Sep. 30, 2015
Inventory Disclosure [Abstract]
Inventories	NOTE E—INVENTORIES At September 30, 2015 and December 31, 2014 , inventories consisted of the following: September 30, December 31, Supplies $ 18,877 $ 17,528 Raw materials and work in process 18,036 12,562 Finished goods 33,758 36,622 Total inventories $ 70,671 $ 66,712

Property, Plant and Mine Develo

Property, Plant and Mine Development	9 Months Ended
	Sep. 30, 2015
Property, Plant and Equipment [Abstract]
Property, Plant and Mine Development	NOTE F—PROPERTY, PLANT AND MINE DEVELOPMENT At September 30, 2015 and December 31, 2014 , property, plant and mine development consisted of the following: September 30, December 31, Mining property and mine development $ 222,611 $ 197,824 Asset retirement cost 10,971 9,559 Land 30,322 28,443 Land improvements 37,058 35,322 Buildings 51,280 47,149 Machinery and equipment 359,792 323,618 Furniture and fixtures 1,647 1,599 Construction-in-progress 47,128 78,997 760,809 722,511 Accumulated depletion, depreciation and amortization (197,547 ) (156,756 ) Total property, plant and mine development, net $ 563,262 $ 565,755 The amount of interest costs capitalized in property, plant and mine development was $465 and $890 for the nine months ended September 30, 2015 and 2014 , respectively.

Debt

Debt	9 Months Ended
	Sep. 30, 2015
Debt Disclosure [Abstract]
Debt	NOTE G—DEBT At September 30, 2015 and December 31, 2014 , debt consisted of the following: September 30, December 31, Senior secured credit facility: Revolver expiring July 23, 2018 (4.75% at September 30, 2015 and 4.75% at December 31, 2014) $ — $ — Term loan facility—final maturity July 23, 2020 (4% - 4.5% at September 30, 2015 and 4% - 5.25% at December 31, 2014) 500,550 504,375 Less: Unamortized original issue discount (1,792 ) (2,078 ) Less: Unamortized debt issuance cost (6,223 ) (7,211 ) Total debt 492,535 495,086 Less: current portion (3,327 ) (3,329 ) Total long-term portion of debt $ 489,208 $ 491,757 Revolving Line-of-Credit We have a $50 million revolving line-of-credit (the “Revolver”), with zero drawn and $3.1 million allocated for letters of credit as of September 30, 2015 , leaving $46.9 million available under the Revolver. Debt Maturities At September 30, 2015 , contractual maturities of long-term debt are as follows: 2015 $ 1,275 2016 5,100 2017 5,100 2018 5,100 2019 5,100 Thereafter 478,875 $ 500,550 Our senior secured credit facility is secured by substantially all of our assets and a pledge of the equity interests in certain of our subsidiaries. The facility contains covenants that, among other things, govern our ability to create, incur or assume indebtedness and liens, to make acquisitions or investments, to pay dividends and to sell assets. The facility also requires us to maintain a consolidated total net leverage ratio of no more than 3.75 :1.00 as of the last day of any fiscal quarter whenever usage of the Revolver (other than certain undrawn letters of credit) exceeds 25% of the Revolver commitment. As of September 30, 2015 , we are in compliance with all covenants in accordance with our senior secured credit facility.

Asset Retirement Obligations

Asset Retirement Obligations	9 Months Ended
	Sep. 30, 2015
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	NOTE H—ASSET RETIREMENT OBLIGATIONS Mine reclamation costs, 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. As of September 30, 2015 , we had a liability of $13.3 million in other long-term obligations related to our asset retirement obligation. Changes in the asset retirement obligation during the nine months ended September 30, 2015 are as follows: September 30, Beginning balance $ 11,283 Payments — Accretion 601 Additions and revisions of prior estimates 1,412 Ending balance $ 13,296

Fair Value Accounting

Fair Value Accounting	9 Months Ended
	Sep. 30, 2015
Fair Value Disclosures [Abstract]
Fair Value Accounting	NOTE I—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 September 30, 2015 and December 31, 2014 approximate their reported carrying values. Short-Term Investments In general, the fair value of our short-term investments is based on quoted prices for similar assets in active markets, or for identical assets or similar assets in markets in which there were fewer transactions (Level 2). Money market mutual funds are based on calculated net asset value and are reported in Level 1. Variable rate demand obligations underwritten and remarketed by a financial institution are priced at par value. 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. Derivative Instruments The estimated fair value of our derivative assets (interest rate caps) are recorded at each reporting period and are based upon widely accepted valuation techniques, including discounted cash flow analysis on the expected cash flows of each derivative contract. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate curves and implied volatilities. We also incorporate credit valuation adjustments to appropriately reflect both our nonperformance risk as well as that of the respective counterparty in the fair value measurements. Although we have determined that the majority of the inputs used to value our derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with our derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default of ourselves and our counterparties. However, as of September 30, 2015 , we have assessed that the impact of the credit valuation adjustments on the overall valuation of our derivative positions is not significant. As a result, we have determined that our derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy. In accordance with the fair value hierarchy, the following table presents the fair value as of September 30, 2015 of those assets that we measure at fair value on a recurring basis: Level 1 Level 2 Total Short-term investments $ 2 $ 46,005 $ 46,007 Interest rate derivatives — — — Net asset $ 2 $ 46,005 $ 46,007

Short-Term Investments

Short-Term Investments	9 Months Ended
	Sep. 30, 2015
Investments, Debt and Equity Securities [Abstract]
Short-Term Investments	NOTE J—SHORT-TERM INVESTMENTS We have segregated funds into designated accounts with investment brokers who manage our short-term investment portfolio. Those funds are held on an available-for-sale basis and are therefore reported at fair value on the balance sheet. The following table summarizes our available-for-sale short-term investments as of September 30, 2015 : Aggregate Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Money market mutual funds $ 2 $ — $ — $ 2 Fixed income securities: Certificates of deposit 16,400 8 — 16,408 Commercial paper 10,174 29 — 10,203 Corporate notes and bonds 8,972 — (31 ) 8,941 Government agencies 8,301 5 (1 ) 8,305 U.S. Treasuries 2,149 — (1 ) 2,148 Total available-for-sale investments $ 45,998 $ 42 $ (33 ) $ 46,007 As of September 30, 2015 , we considered any declines in market value of our short-term investment portfolio to be temporary in nature and did not consider any of our investments other-than-temporarily impaired. We typically invest in highly-rated securities, and our investment policy generally limits the amount of credit exposure to any one issuer. The policy requires investments generally to be investment grade, with the primary objective of minimizing the potential risk of principal loss. Fair values were determined for each individual security in the investment portfolio. When evaluating an investment for other-than-temporary impairment, we review factors such as the length of time and extent to which fair value has been below its cost basis, the financial condition of the issuer and any changes thereto, changes in market interest rates, and our intent to sell, or whether it is more likely than not it will be required to sell, the investment before recovery of the investment’s cost basis. As of September 30, 2015 , we did no t recognize any impairment charges.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	NOTE K—COMMITMENTS AND CONTINGENCIES Future Minimum Annual Commitments at September 30, 2015 : Operating Leases Minimum Purchase Commitments 2015 $ 11,500 $ 9,909 2016 44,436 31,834 2017 55,742 20,852 2018 59,040 16,664 2019 53,549 11,717 Thereafter 180,823 16,921 Total future lease and purchase commitments $ 405,090 $ 107,897 Operating Leases We are obligated under certain operating leases for railroad cars, office space, mining property, mining/processing equipment and transportation and other equipment. Certain operating lease agreements include options to purchase the equipment for fair market value at the end of the original lease term. In general, the above leases include renewal options and provide that we pay for all utilities, insurance, taxes and maintenance. Expense related to operating leases and rental agreements totaled approximately $13.2 million and $8.1 million for the three months ended September 30, 2015 and 2014 , respectively, and $34.9 million and $23.4 million for the nine months ended September 30, 2015 and 2014 , respectively. As of September 30, 2015 , we have no obligations under a capital lease. Minimum Purchase Commitments We enter into service agreements with our transload service providers and transportation service providers. 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. 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 three months ended September 30, 2015 , no new claims were brought against U.S. Silica. As of September 30, 2015 , there were 75 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. For periods prior to 1986, U.S. Silica had numerous insurance policies and an indemnity from a former owner that covered silicosis claims. In the fourth quarter of 2012, U.S. Silica settled all rights under the indemnity and its underlying insurance. The settlement was received during the first quarter of 2013. As a result of the settlement, the indemnity and related policies are no longer available to U.S. Silica and U.S. Silica will not seek reimbursement for any defense costs or claim payments. Other insurance policies, however, continue to remain available to U.S. Silica. We have recorded estimated liabilities for these claims in other long-term obligations as well as estimated recoveries under the indemnity agreement and an estimate of future recoveries under insurance in other assets on our consolidated balance sheets. As of both September 30, 2015 , and December 31, 2014 other non-current assets included $0.3 million for insurance for third-party products liability claims and other long-term obligations included $1.3 million in third-party products claims liability. Additionally, during the three months ended March 31, 2015, we received an unfavorable ruling in an arbitration proceeding as a result of exiting a toll manufacturing contract. The amount of the ruling was approximately $7.6 million . The matter was settled and the settlement amount of $6.5 million was paid on June 9, 2015, which was included in selling, general and administrative expense in our Income Statement for the nine months ended September 30, 2015 .

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2015
Income Tax Disclosure [Abstract]
Income Taxes	NOTE L—INCOME TAXES For interim period reporting, we record income taxes using an estimated annual effective tax rate based upon projected annual income, forecasted permanent tax differences, discrete items and statutory rates in states in which we operate. At the end of each interim period, we update the estimated annual effective tax rate, and if the estimated tax rate changes based on new information, we make a cumulative adjustment in the period. We record the tax effect of an unusual or infrequently occurring item in the interim period in which it occurs as a discrete item of tax. In the nine months ended September 30, 2015 , we recorded a discrete tax benefit of $2.9 million , which relates to the arbitration ruling described in Note K - Commitments and Contingencies . The effective tax rate was (39)% and 27% for nine months ended September 30, 2015 and 2014 , respectively. The tax rate for the nine months ending September 30, 2015 would have been (24)% without the discrete tax benefit. Historically, our actual effective tax rates have been lower than the statutory effective rate primarily due to the benefit received from statutory percentage depletion allowances. The deduction for statutory percentage depletion does not necessarily change proportionately to changes in income before income taxes.

Pension and Post-Retirement Ben

Pension and Post-Retirement Benefits	9 Months Ended
	Sep. 30, 2015
Compensation and Retirement Disclosure [Abstract]
Pension and Post-Retirement Benefits	NOTE M—PENSION AND POST-RETIREMENT BENEFITS We maintain a single-employer noncontributory defined benefit pension plan covering certain employees. Net pension benefit cost recognized for the three and nine months ended September 30, 2015 and 2014 are as follows: Three Months Ended Nine Months Ended 2015 2014 2015 2014 Service cost $ 324 $ 269 $ 971 $ 808 Interest cost 1,203 1,143 3,610 3,428 Expected return on plan assets (1,375 ) (1,255 ) (4,124 ) (3,765 ) Net amortization and deferral 666 237 1,999 713 Net pension benefit costs $ 818 $ 394 $ 2,456 $ 1,184 In addition, we provide defined benefit post-retirement health care and life insurance benefits to some employees. Net periodic post-retirement benefit cost recognized for the three and nine months ended September 30, 2015 and 2014 are as follows: Three Months Ended Nine Months Ended 2015 2014 2015 2014 Service cost $ 36 $ 45 $ 124 $ 135 Interest cost 221 256 776 770 Expected return on plan assets — (1 ) (2 ) (3 ) Special termination benefit 47 — 47 — Net amortization and deferral 58 — 250 — Net post-retirement costs $ 362 $ 300 $ 1,195 $ 902 The weighted average discount rate used to determine the projected pension and post-retirement obligations was updated during the nine months ended September 30, 2015 , and was increased from 4.1% at December 31, 2014 to 4.3% at September 30, 2015 . We contributed $1.8 million and $2.0 million to the qualified pension plan for the three months ended September 30, 2015 and 2014, respectively. We contributed $2.0 million and $4.6 million to the qualified pension plan during the nine months ended September 30, 2015 and 2014 , respectively. Total expected employer funding contributions during the fiscal year ending December 31, 2015 are $2.0 million for the pension plan and $1.6 million for the post-retirement medical and life plan.

Obligations under Guarantees

Obligations under Guarantees	9 Months Ended
	Sep. 30, 2015
Guarantees [Abstract]
Obligations Under Guarantees	NOTE N—OBLIGATIONS UNDER GUARANTEES We have indemnified Travelers Casualty and Surety Company of America (“Travelers”) against any loss Travelers may incur in the event that holders of surety bonds, issued on behalf of us by Travelers, execute the bonds. As of September 30, 2015 , Travelers had $9.9 million in bonds outstanding for us. The majority of these bonds, $9.5 million , relate to reclamation requirements issued by various governmental authorities. Reclamation bonds remain outstanding until the mining area is reclaimed and the authority issues a formal release. The remaining bonds relate to such indefinite purposes as licenses, permits, and tax collection.

Segment Reporting

Segment Reporting	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Segment Reporting	NOTE O—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 by providing 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 260 products and materials used in a variety of industries, including container glass, fiberglass, specialty glass, flat glass, building products, fillers and extenders, foundry products, chemicals, recreation products and filtration products. An operating segment’s performance is primarily evaluated based on segment contribution margin, which excludes certain corporate costs not associated with the operations of the segment. These corporate costs are separately stated below and include costs that are related to functional areas such as operations management, corporate purchasing, accounting, treasury, information technology, legal and human resources. We believe that segment contribution margin, as defined above, is an appropriate measure for evaluating the operating performance of our segments. However, this measure should be considered in addition to, not a substitute for, or superior to, income from operations or other measures of financial performance prepared in accordance with generally accepted accounting principles. The other accounting policies of each of the two reporting segments are the same as those in Note A - Summary of Significant Accounting Policies of our Financial Statements. The following table presents sales and segment contribution margin for the reporting segments and other operating results not allocated to the reported segments for the three and nine months ended September 30, 2015 and 2014 : Three Months Ended Nine Months Ended 2015 2014 2015 2014 Sales: Oil & Gas Proppants $ 101,987 $ 186,812 $ 341,593 $ 466,727 Industrial & Specialty Products 53,421 54,444 165,284 160,425 Total Sales 155,408 241,256 506,877 627,152 Segment contribution margin: Oil & Gas Proppants 16,521 77,030 81,972 175,718 Industrial & Specialty Products 19,967 16,844 54,953 47,646 Total segment contribution margin 36,488 93,874 136,925 223,364 Operating activities excluded from segment cost of goods sold (3,679 ) (2,315 ) (8,500 ) (5,096 ) Selling, general and administrative (13,559 ) (18,600 ) (47,095 ) (53,312 ) Depreciation, depletion and amortization (15,158 ) (12,425 ) (42,096 ) (32,355 ) Interest expense (6,684 ) (4,950 ) (20,448 ) (12,771 ) Other income, net, including interest income 309 120 818 379 Income/(loss) before income taxes $ (2,283 ) $ 55,704 $ 19,604 $ 120,209 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. Goodwill of $68.6 million has been allocated to these segments with $47.9 million assigned to Oil & Gas Proppants and $20.7 million to Industrial & Specialty Products.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2015
Subsequent Events [Abstract]
Subsequent Events	NOTE P—SUBSEQUENT EVENTS On October 2, 2015 , we paid a cash dividend of $ 0.125 per share to common stockholders of record on September 15, 2015 , which had been declared by our Board of Directors on July 24, 2015 .

Summary of Significant Accoun25

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2015
Accounting Policies [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The accompanying Condensed Consolidated Financial Statements (the “Financial Statements”) of U.S. Silica Holdings, Inc. (“Holdings,” and together with its subsidiaries “we,” “us” or the “Company”) included in this Quarterly Report on Form 10-Q, have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X issued by the U.S. Securities and Exchange Commission (“SEC”). They do not contain certain information included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2014 ; therefore, the interim Condensed Consolidated Financial Statements should be read in conjunction with that Annual Report on Form 10-K. In the opinion of management, all adjustments necessary for a fair presentation of the Financial Statements have been included. Such adjustments are of a normal, recurring nature. We have reclassified certain immaterial amounts in the prior years’ assets section of the consolidated balance sheets and operating activities section of the consolidated statement of cash flows to conform to the current year presentation. These reclassifications had no effect on previously reported total assets and net cash flows from operations. In order to make this report easier to read, we refer throughout to (i) our Condensed Consolidated Balance Sheets as our “Balance Sheets,” (ii) our Condensed Consolidated Statements of Operations as our “Income Statements,” and (iii) our Condensed Consolidated Statements of Cash Flows as our “Cash Flows.”
Unaudited Interim Financial Statements	Unaudited Interim Financial Statements The accompanying Balance Sheet as of September 30, 2015 ; the Income Statements for the three and nine months ended September 30, 2015 and 2014 ; the Condensed Consolidated Statements of Comprehensive Income for the three and nine months ended September 30, 2015 and 2014 ; the Condensed Consolidated Statements of Stockholders' Equity for the nine months ended September 30, 2015 ; the Cash Flows for the nine months ended September 30, 2015 and 2014 ; and other information disclosed in the related notes are unaudited. The Balance Sheet as of December 31, 2014 was derived from our audited consolidated financial statements as included in our 2014 Annual Report.
Use of Estimates and Assumptions	Use of Estimates and Assumptions The preparation of the Financial Statements requires us 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 Financial Statements and the reported amounts of revenues and expenses during the reporting period. The more significant areas requiring the use of management estimates and assumptions relate to 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 doubtful accounts; estimates of fair value for certain reporting units and asset impairments (including impairments of goodwill 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; reserves for contingencies and litigation; and the fair value and accounting treatment of financial instruments including derivative 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.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In April 2015, the Financial Accounting Standards Board ("FASB") issued an Accounting Standards Update, Interest-Imputation of Interest, which simplifies presentation of debt issuance costs. The new standard requires that debt issuance costs be presented in the balance sheet as a direct deduction from the carrying amount of debt liability, consistent with debt discounts or premiums. The new standard will be effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within fiscal years beginning after December 15, 2016. Early adoption of the amendments in this Update is permitted for financial statements that have not been previously issued. We have elected to adopt the standard early and have presented debt issuance costs as a direct deduction from the carrying amount of debt on our Balance Sheets as of September 30, 2015 and December 31, 2014 . On July 22, 2015, the FASB issued Accounting Standards Update, Simplifying the Measurement of Inventory. The new standard requires an entity to measure most inventory at the lower of cost and net realizable value, thereby simplifying the current guidance under which an entity must measure inventory at the lower of cost or market. The new standard will not apply to inventories that are measured using either the last-in, first-out (LIFO) method or the retail inventory method. This Update is effective for public entities for financial statements issued for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years; early application is permitted. We are currently evaluating the effect that the new guidance will have on our financial statements and related disclosures.

Capital Structure and Accumul26

Capital Structure and Accumulated Comprehensive Income (Tables)	9 Months Ended
	Sep. 30, 2015
Equity [Abstract]
Schedule of Quarterly Cash Dividends	In 2015 , our Board of Directors declared quarterly cash dividends as follows: Dividends per Common Share Declaration Date Record Date Payable Date $ 0.125 February 12, 2015 March 16, 2015 April 3, 2015 $ 0.125 May 8, 2015 June 15, 2015 July 6, 2015 $ 0.125 July 24, 2015 September 15, 2015 October 2, 2015
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	The weighted-average stock options that are antidilutive and are therefore excluded from the calculation of our diluted earnings per common share are: Three Months Ended Nine Months Ended 2015 2014 2015 2014 Weighted-average outstanding stock options excluded 726 — 464 —
Changes in Accumulated Other Comprehensive Income	The following table presents the changes in accumulated other comprehensive income by component during the nine months ended September 30, 2015 : For the Nine Months Ended September 30, 2015 Unrealized gain/(loss) on cash flow hedges Unrealized gain/(loss) on short-term investments Pension and other post-retirement benefits liability Total Beginning Balance $ (134 ) $ (41 ) $ (19,643 ) $ (19,818 ) Other comprehensive income (loss) before reclassifications (3 ) 53 (1,127 ) (1,077 ) Amounts reclassed from accumulated other comprehensive income 32 — 1,381 1,413 Ending Balance $ (105 ) $ 12 $ (19,389 ) $ (19,482 )

Business Combination (Tables)

Business Combination (Tables)	9 Months Ended
	Sep. 30, 2015
Business Combinations [Abstract]
Schedule of Purchase Price Allocation	The table below represents the tangible and identifiable intangible assets and liabilities based on management’s assessment of the acquisition date fair value of the assets acquired and liabilities assumed: Accounts receivable $ 6,898 Inventory 2,534 Other current assets 174 Fixed assets 73,138 Deferred tax assets (net) 13,966 Accounts payable, accrued expenses and other liabilities (4,389 ) Net tangible assets acquired 92,321 Customer relationships 1,274 Trade name 4,478 Goodwill 244 Purchase price, net of cash acquired $ 98,317
Schedule of Intangible Assets Acquired as Part of Business Combination	The value of acquired intangible assets and the related estimated useful lives consist of the following: Estimated Useful Lives Value Customer relationships 15 years $ 1,274 Trade name Indefinite 4,478 Total intangible assets $ 5,752
Schedule of Pro Forma Financial Information	The following unaudited pro forma consolidated financial information reflects the results of operations as if the Cadre acquisition had occurred on January 1, 2014, after giving effect to certain purchase accounting adjustments. This information does not purport to be indicative of the actual results that would have occurred if the acquisition had actually been completed on the date indicated, nor is it necessarily indicative of the future operating results or the financial position of the combined company: Three Months Ended Nine Months Ended Sales $ 245,625 $ 652,288 Net income 42,466 92,349 Basic earnings per share $ 0.79 $ 1.72 Diluted earnings per share 0.78 1.70

Accounts Receivable (Tables)

Accounts Receivable (Tables)	9 Months Ended
	Sep. 30, 2015
Receivables [Abstract]
Schedule of Accounts Receivable	At September 30, 2015 and December 31, 2014 , accounts receivable consisted of the following: September 30, December 31, Trade receivables $ 93,404 $ 128,498 Less: Allowance for doubtful accounts (9,118 ) (10,429 ) Net trade receivables 84,286 118,069 Other receivables 1,319 2,812 Total accounts receivable $ 85,605 $ 120,881 Changes in our allowance for doubtful accounts during the nine months ended September 30, 2015 are as follows: September 30, Beginning balance $ 10,429 Bad debt provision (211 ) Write-offs (1,100 ) Ending balance $ 9,118

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 30, 2015
Inventory Disclosure [Abstract]
Schedule of Inventories	At September 30, 2015 and December 31, 2014 , inventories consisted of the following: September 30, December 31, Supplies $ 18,877 $ 17,528 Raw materials and work in process 18,036 12,562 Finished goods 33,758 36,622 Total inventories $ 70,671 $ 66,712

Property, Plant and Mine Deve30

Property, Plant and Mine Development (Tables)	9 Months Ended
	Sep. 30, 2015
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and Mine Development	At September 30, 2015 and December 31, 2014 , property, plant and mine development consisted of the following: September 30, December 31, Mining property and mine development $ 222,611 $ 197,824 Asset retirement cost 10,971 9,559 Land 30,322 28,443 Land improvements 37,058 35,322 Buildings 51,280 47,149 Machinery and equipment 359,792 323,618 Furniture and fixtures 1,647 1,599 Construction-in-progress 47,128 78,997 760,809 722,511 Accumulated depletion, depreciation and amortization (197,547 ) (156,756 ) Total property, plant and mine development, net $ 563,262 $ 565,755

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2015
Debt Disclosure [Abstract]
Schedule of Debt	At September 30, 2015 and December 31, 2014 , debt consisted of the following: September 30, December 31, Senior secured credit facility: Revolver expiring July 23, 2018 (4.75% at September 30, 2015 and 4.75% at December 31, 2014) $ — $ — Term loan facility—final maturity July 23, 2020 (4% - 4.5% at September 30, 2015 and 4% - 5.25% at December 31, 2014) 500,550 504,375 Less: Unamortized original issue discount (1,792 ) (2,078 ) Less: Unamortized debt issuance cost (6,223 ) (7,211 ) Total debt 492,535 495,086 Less: current portion (3,327 ) (3,329 ) Total long-term portion of debt $ 489,208 $ 491,757
Schedule of Contractual Maturities of Debt	At September 30, 2015 , contractual maturities of long-term debt are as follows: 2015 $ 1,275 2016 5,100 2017 5,100 2018 5,100 2019 5,100 Thereafter 478,875 $ 500,550

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	9 Months Ended
	Sep. 30, 2015
Asset Retirement Obligation Disclosure [Abstract]
Schedule of Changes in Asset Retirement Obligation	Changes in the asset retirement obligation during the nine months ended September 30, 2015 are as follows: September 30, Beginning balance $ 11,283 Payments — Accretion 601 Additions and revisions of prior estimates 1,412 Ending balance $ 13,296

Fair Value Accounting (Tables)

Fair Value Accounting (Tables)	9 Months Ended
	Sep. 30, 2015
Fair Value Disclosures [Abstract]
Schedule of Measure at Fair Value on Recurring Basis	In accordance with the fair value hierarchy, the following table presents the fair value as of September 30, 2015 of those assets that we measure at fair value on a recurring basis: Level 1 Level 2 Total Short-term investments $ 2 $ 46,005 $ 46,007 Interest rate derivatives — — — Net asset $ 2 $ 46,005 $ 46,007

Short-Term Investments (Tables)

Short-Term Investments (Tables)	9 Months Ended
	Sep. 30, 2015
Investments, Debt and Equity Securities [Abstract]
Summary of Available-for-Sale Short-Term Investments	The following table summarizes our available-for-sale short-term investments as of September 30, 2015 : Aggregate Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Money market mutual funds $ 2 $ — $ — $ 2 Fixed income securities: Certificates of deposit 16,400 8 — 16,408 Commercial paper 10,174 29 — 10,203 Corporate notes and bonds 8,972 — (31 ) 8,941 Government agencies 8,301 5 (1 ) 8,305 U.S. Treasuries 2,149 — (1 ) 2,148 Total available-for-sale investments $ 45,998 $ 42 $ (33 ) $ 46,007

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Annual Commitments	Future Minimum Annual Commitments at September 30, 2015 : Operating Leases Minimum Purchase Commitments 2015 $ 11,500 $ 9,909 2016 44,436 31,834 2017 55,742 20,852 2018 59,040 16,664 2019 53,549 11,717 Thereafter 180,823 16,921 Total future lease and purchase commitments $ 405,090 $ 107,897

Pension and Post-Retirement B36

Pension and Post-Retirement Benefits (Tables)	9 Months Ended
	Sep. 30, 2015
Compensation and Retirement Disclosure [Abstract]
Summarizes Information about Pension and Post-Retirement Benefit Plans	We maintain a single-employer noncontributory defined benefit pension plan covering certain employees. Net pension benefit cost recognized for the three and nine months ended September 30, 2015 and 2014 are as follows: Three Months Ended Nine Months Ended 2015 2014 2015 2014 Service cost $ 324 $ 269 $ 971 $ 808 Interest cost 1,203 1,143 3,610 3,428 Expected return on plan assets (1,375 ) (1,255 ) (4,124 ) (3,765 ) Net amortization and deferral 666 237 1,999 713 Net pension benefit costs $ 818 $ 394 $ 2,456 $ 1,184 In addition, we provide defined benefit post-retirement health care and life insurance benefits to some employees. Net periodic post-retirement benefit cost recognized for the three and nine months ended September 30, 2015 and 2014 are as follows: Three Months Ended Nine Months Ended 2015 2014 2015 2014 Service cost $ 36 $ 45 $ 124 $ 135 Interest cost 221 256 776 770 Expected return on plan assets — (1 ) (2 ) (3 ) Special termination benefit 47 — 47 — Net amortization and deferral 58 — 250 — Net post-retirement costs $ 362 $ 300 $ 1,195 $ 902

Segment Reporting (Tables)

Segment Reporting (Tables)	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Presentation of Sales and Segment Contribution Margin for Reporting Segments and Other Operating Results	The following table presents sales and segment contribution margin for the reporting segments and other operating results not allocated to the reported segments for the three and nine months ended September 30, 2015 and 2014 : Three Months Ended Nine Months Ended 2015 2014 2015 2014 Sales: Oil & Gas Proppants $ 101,987 $ 186,812 $ 341,593 $ 466,727 Industrial & Specialty Products 53,421 54,444 165,284 160,425 Total Sales 155,408 241,256 506,877 627,152 Segment contribution margin: Oil & Gas Proppants 16,521 77,030 81,972 175,718 Industrial & Specialty Products 19,967 16,844 54,953 47,646 Total segment contribution margin 36,488 93,874 136,925 223,364 Operating activities excluded from segment cost of goods sold (3,679 ) (2,315 ) (8,500 ) (5,096 ) Selling, general and administrative (13,559 ) (18,600 ) (47,095 ) (53,312 ) Depreciation, depletion and amortization (15,158 ) (12,425 ) (42,096 ) (32,355 ) Interest expense (6,684 ) (4,950 ) (20,448 ) (12,771 ) Other income, net, including interest income 309 120 818 379 Income/(loss) before income taxes $ (2,283 ) $ 55,704 $ 19,604 $ 120,209

Earnings Per Share - Schedule o

Earnings Per Share - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Employee Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average outstanding stock options excluded	726	0	464	0

Capital Structure and Accumul39

Capital Structure and Accumulated Comprehensive Income (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Capital Structure And Accumulated Comprehensive Income (Loss)
Common stock issued (shares)	53,386,174	53,902,295
Common stock outstanding (shares)	53,386,174	53,902,295
Preferred stock issued (shares)	0	0
Preferred stock outstanding (shares)	0	0
Authorization to repurchase common stock	$ 50,000,000
Repurchase of common stock (shares)	706,093
Average price per common share of repurchase common stock (in USD per share)	$ 23.83
Remaining authorized repurchase of common stock amount	$ 33,200,000
Common Stock
Capital Structure And Accumulated Comprehensive Income (Loss)
Common stock authorized (shares)	500,000,000
Common stock, par value	$ 0.01
Preferred Stock
Capital Structure And Accumulated Comprehensive Income (Loss)
Preferred stock authorized (shares)	10,000,000
Preferred stock, par value	$ 0.01

Capital Structure and Accumul40

Capital Structure and Accumulated Comprehensive Income - Schedule of Quarterly Cash Dividends (Details) - $ / shares	3 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015
Equity [Abstract]
Dividends per common share	$ 0.125		$ 0.125
Declaration date	Jul. 24, 2015	May 8, 2015	Feb. 12, 2015
Record date	Sep. 15, 2015	Jun. 15, 2015	Mar. 16, 2015
Payable date	Oct. 2, 2015	Jul. 6, 2015	Apr. 3, 2015

Capital Structure and Accumul41

Capital Structure and Accumulated Comprehensive Income - Changes in Accumulated Other Comprehensive Income (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ (19,818)
Other comprehensive income (loss) before reclassifications	(1,077)
Amounts reclassed from accumulated other comprehensive income	1,413
Ending Balance	(19,482)
Unrealized Gains and Losses on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(134)
Other comprehensive income (loss) before reclassifications	(3)
Amounts reclassed from accumulated other comprehensive income	32
Ending Balance	(105)
Unrealized Gain/(Loss) on Short-Term Investments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(41)
Other comprehensive income (loss) before reclassifications	53
Amounts reclassed from accumulated other comprehensive income	0
Ending Balance	12
Pension and Other Postretirement Benefits Liability
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(19,643)
Other comprehensive income (loss) before reclassifications	(1,127)
Amounts reclassed from accumulated other comprehensive income	1,381
Ending Balance	$ (19,389)

Business Combination (Details)

Business Combination (Details) - USD ($)	Jul. 31, 2014	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2015	Dec. 31, 2014
Business Acquisition
Sales		$ 245,625,000	$ 652,288,000
Goodwill				$ 68,647,000	$ 68,647,000
Net income		$ 42,466,000	$ 92,349,000
Business Acquisition, Pro Forma Earnings Per Share, Basic		$ 0.79	$ 1.72
Business Acquisition, Pro Forma Earnings Per Share, Diluted		$ 0.78	$ 1.70
Cadre Services, Inc.
Business Acquisition
Total purchase price	$ 98,300,000
Goodwill	244,000
Goodwill expected to be tax deductible	$ 0

Business Combination - Schedule

Business Combination - Schedule of Purchase Price Allocation (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Jul. 31, 2014
Business Acquisition
Goodwill	$ 68,647	$ 68,647
Cadre Services, Inc.
Business Acquisition
Accounts receivable			$ 6,898
Inventory			2,534
Other current assets			174
Fixed assets			73,138
Deferred tax assets (net)			13,966
Accounts payable, accrued expenses and other liabilities			(4,389)
Net tangible assets acquired			92,321
Total intangible assets			5,752
Goodwill			244
Purchase price, net of cash acquired			98,317
Customer Relationships | Cadre Services, Inc.
Business Acquisition
Total intangible assets			1,274
Trade Names | Cadre Services, Inc.
Business Acquisition
Total intangible assets			$ 4,478

Business Combination - Schedu44

Business Combination - Schedule of Intangible Assets Acquired as Part of Business Combination (Details) - Cadre Services, Inc. $ in Thousands	Jul. 31, 2014USD ($)
Business Acquisition
Total intangible assets	$ 5,752
Customer Relationships
Business Acquisition
Estimated Useful Lives	15 years
Total intangible assets	$ 1,274
Trade Names
Business Acquisition
Total intangible assets	$ 4,478

Business Combination - Schedu45

Business Combination - Schedule of Pro Forma Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014
Business Combinations [Abstract]
Sales	$ 245,625	$ 652,288
Net income	$ 42,466	$ 92,349
Business Acquisition, Pro Forma Earnings Per Share, Basic	$ 0.79	$ 1.72
Business Acquisition, Pro Forma Earnings Per Share, Diluted	$ 0.78	$ 1.70

Accounts Receivable - Schedule

Accounts Receivable - Schedule of Accounts Receivable (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Receivables [Abstract]
Trade receivables	$ 93,404	$ 128,498
Less: Allowance for doubtful accounts	(9,118)	(10,429)
Net trade receivables	84,286	118,069
Other receivables	1,319	2,812
Total accounts receivable	$ 85,605	$ 120,881

Accounts Receivable - Allowance

Accounts Receivable - Allowance for Doubtful Accounts (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)
Allowance for Doubtful Accounts Receivable
Beginning balance	$ 10,429
Bad debt provision	(211)
Write-offs	(1,100)
Ending balance	$ 9,118

Inventories - Schedule of Inven

Inventories - Schedule of Inventories (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Supplies	$ 18,877	$ 17,528
Raw materials and work in process	18,036	12,562
Finished goods	33,758	36,622
Total inventories	$ 70,671	$ 66,712

Property, Plant and Mine Deve49

Property, Plant and Mine Development (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Property, Plant and Equipment
Interest Costs Capitalized	$ 465	$ 890

Property, Plant and Mine Deve50

Property, Plant and Mine Development - Schedule of Property, Plant and Mine Development (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Property, Plant and Equipment
Interest Costs Capitalized	$ 465	$ 890
Property, plant and mine development	760,809		$ 722,511
Accumulated depletion, depreciation and amortization	(197,547)		(156,756)
Total property, plant and mine development, net	563,262		565,755
Mining Property and Mine Development
Property, Plant and Equipment
Property, plant and mine development	222,611		197,824
Asset Retirement Cost
Property, Plant and Equipment
Property, plant and mine development	10,971		9,559
Land
Property, Plant and Equipment
Property, plant and mine development	30,322		28,443
Land Improvements
Property, Plant and Equipment
Property, plant and mine development	37,058		35,322
Buildings
Property, Plant and Equipment
Property, plant and mine development	51,280		47,149
Machinery and Equipment
Property, Plant and Equipment
Property, plant and mine development	359,792		323,618
Furniture and Fixtures
Property, Plant and Equipment
Property, plant and mine development	1,647		1,599
Construction-in-Progress
Property, Plant and Equipment
Property, plant and mine development	$ 47,128		$ 78,997

Debt (Detail)

Debt (Detail)	9 Months Ended
	Sep. 30, 2015USD ($)
Short-term Debt
Credit facility consolidated total net leverage ratio	0.0375
Net leverage ratio, credit facility threshold (percentage)	25.00%
Revolving Line-of-Credit
Short-term Debt
Available borrowing base	$ 50,000,000
Amount drawn from borrowing base	0
Amount available for general corporate use under this revolving credit agreement	46,900,000
Letter of Credit
Short-term Debt
Amount allocated for letters of credit	$ 3,100,000

Debt - Schedule of Debt (Detail

Debt - Schedule of Debt (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Line of Credit Facility
Less: Unamortized debt issuance cost	$ (6,223)	$ (7,211)
Total debt	492,535	495,086
Less: current portion	(3,327)	(3,329)
Total long-term portion of debt	489,208	491,757
Revolving Line-of-Credit
Line of Credit Facility
Total debt	$ 0	$ 0
Credit facility, maturity date	Jul. 23, 2018
Credit facility, interest rate	4.75%	4.75%
Term Loan Facility
Line of Credit Facility
Less: Unamortized original issue discount	$ (1,792)	$ (2,078)
Total debt	$ 500,550	$ 504,375
Credit facility, maturity date	Jul. 23, 2020
Minimum | Term Loan Facility
Line of Credit Facility
Credit facility, interest rate	4.00%	4.00%
Maximum | Term Loan Facility
Line of Credit Facility
Credit facility, interest rate	4.50%	5.25%

Debt - Schedule of Contractual

Debt - Schedule of Contractual Maturities of Debt (Detail) $ in Thousands	Sep. 30, 2015USD ($)
Debt Disclosure [Abstract]
2,015	$ 1,275
2,016	5,100
2,017	5,100
2,018	5,100
2,019	5,100
Thereafter	478,875
Total debt	$ 500,550

Asset Retirement Obligations (D

Asset Retirement Obligations (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligation	$ 13,296	$ 11,283

Asset Retirement Obligations -

Asset Retirement Obligations - Schedule of Changes in Asset Retirement Obligation (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)
Asset Retirement Obligation Disclosure [Abstract]
Beginning balance	$ 11,283
Payments	0
Accretion	601
Additions and revisions of prior estimates	1,412
Ending balance	$ 13,296

Fair Value Accounting - Schedul

Fair Value Accounting - Schedule of Measure at Fair Value on Recurring Basis (Detail) - Measured at Fair Value on Recurring Basis $ in Thousands	Sep. 30, 2015USD ($)
Defined Benefit Plan Disclosure
Short-term investments	$ 46,007
Interest rate derivatives	0
Net asset	46,007
Level 1
Defined Benefit Plan Disclosure
Short-term investments	2
Interest rate derivatives	0
Net asset	2
Level 2
Defined Benefit Plan Disclosure
Short-term investments	46,005
Interest rate derivatives	0
Net asset	$ 46,005

Short-Term Investments (Detail)

Short-Term Investments (Detail)	9 Months Ended
	Sep. 30, 2015USD ($)
Investments, Debt and Equity Securities [Abstract]
Impairment charges	$ 0

Short-Term Investments - Schedu

Short-Term Investments - Schedule of Available-for-Sale Short-Term Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities
Aggregate Cost	$ 45,998
Gross Unrealized Gains	42
Gross Unrealized Losses	(33)
Fair Value	46,007	$ 75,143
Money Market Mutual Funds
Schedule of Available-for-sale Securities
Aggregate Cost	2
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Fair Value	2
Certificates Of Deposit
Schedule of Available-for-sale Securities
Aggregate Cost	16,400
Gross Unrealized Gains	8
Gross Unrealized Losses	0
Fair Value	16,408
Commercial Paper
Schedule of Available-for-sale Securities
Aggregate Cost	10,174
Gross Unrealized Gains	29
Gross Unrealized Losses	0
Fair Value	10,203
Corporate Notes And Bonds
Schedule of Available-for-sale Securities
Aggregate Cost	8,972
Gross Unrealized Gains	0
Gross Unrealized Losses	(31)
Fair Value	8,941
Government Agencies
Schedule of Available-for-sale Securities
Aggregate Cost	8,301
Gross Unrealized Gains	5
Gross Unrealized Losses	(1)
Fair Value	8,305
US Treasuries
Schedule of Available-for-sale Securities
Aggregate Cost	2,149
Gross Unrealized Gains	0
Gross Unrealized Losses	(1)
Fair Value	$ 2,148

Commitments and Contingencies59

Commitments and Contingencies (Detail) $ in Thousands	3 Months Ended			6 Months Ended	9 Months Ended
	Sep. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Sep. 30, 2014USD ($)	Jun. 30, 2015USD ($)	Sep. 30, 2015USD ($)claim	Sep. 30, 2014USD ($)	Dec. 31, 2014USD ($)
Insurance [Abstract]
Expenses related to operating leases and rental agreements	$ 13,200		$ 8,100		$ 34,900	$ 23,400
New claims filed | claim					0
Third party products claims liability under insurance in other assets	300				$ 300		$ 311
Third party products claims liability under insurance in other long-term obligations	$ 1,300				$ 1,300		$ 1,600
Selling, General and Administrative Expense
Loss Contingencies
Litigation settlement expense		$ 7,600
Payments for Legal Settlements				$ 6,500

Commitments and Contingencies -

Commitments and Contingencies - Schedule of Future Minimum Annual Commitments (Details) $ in Thousands	Sep. 30, 2015USD ($)
Operating Leases
2,015	$ 11,500
2,016	44,436
2,017	55,742
2,018	59,040
2,019	53,549
Thereafter	180,823
Total future lease commitments	405,090
Minimum Purchase Commitments
2,015	9,909
2,016	31,834
2,017	20,852
2,018	16,664
2,019	11,717
Thereafter	16,921
Total future purchase commitments	$ 107,897

Income Taxes (Details)

Income Taxes (Details) $ in Millions	3 Months Ended	9 Months Ended
	Mar. 31, 2015USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2014
Loss Contingencies
Discrete tax benefit related to unfavorable ruling		$ 2.9
Effective income tax rate		(39.00%)	27.00%
Effective income tax rate without discrete tax benefit		(0.24)
Selling, General and Administrative Expense
Loss Contingencies
Litigation settlement expense	$ 7.6

Pension and Post-Retirement B62

Pension and Post-Retirement Benefits (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Defined Benefit Plan Disclosure
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.30%		4.30%		4.10%
Pension Benefits
Defined Benefit Plan Disclosure
Contributions to plan by employer	$ 1.8	$ 2	$ 2	$ 4.6
Expected contributions in current fiscal year			2
Post-retirement Benefits
Defined Benefit Plan Disclosure
Expected contributions in current fiscal year			$ 1.6

Pension and Post-Retirement B63

Pension and Post-Retirement Benefits - Summarizes Information about Pension and Post-Retirement Benefit Plans (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Pension Benefits
Defined Benefit Plan Disclosure
Service cost	$ 324	$ 269	$ 971	$ 808
Interest cost	1,203	1,143	3,610	3,428
Expected return on plan assets	(1,375)	(1,255)	(4,124)	(3,765)
Net amortization and deferral	666	237	1,999	713
Net pension benefit costs	818	394	2,456	1,184
Post-retirement Benefits
Defined Benefit Plan Disclosure
Service cost	36	45	124	135
Interest cost	221	256	776	770
Expected return on plan assets	0	(1)	(2)	(3)
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	(47)	0	(47)	0
Net amortization and deferral	58	0	250	0
Net pension benefit costs	$ 362	$ 300	$ 1,195	$ 902

Obligations Under Guarantees (D

Obligations Under Guarantees (Detail) - Travelers Casualty and Surety Company $ in Millions	Sep. 30, 2015USD ($)
Surety Bonds
Loss Contingencies
Surety bonds outstanding	$ 9.9
Reclamation Bonds
Loss Contingencies
Bonds related to reclamation requirements	$ 9.5

Segment Reporting (Detail)

Segment Reporting (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)SegmentProduct	Dec. 31, 2014USD ($)
Segment Reporting Information
Number of reportable segments | Segment	2
Number of products in Industrial & Specialty segment (over 260) | Product	260
Goodwill	$ 68,647	$ 68,647
Industrial & Specialty Products segment description	Over 260 products and materials used in a variety of industries including, container glass, fiberglass, specialty glass, flat glass, building products, fillers and extenders, foundry products, chemicals, recreation products and filtration products.
Oil & Gas Proppants
Segment Reporting Information
Goodwill	$ 47,900
Industrial & Specialty Products
Segment Reporting Information
Goodwill	$ 20,700

Segment Reporting - Presentatio

Segment Reporting - Presentation of Sales and Segment Contribution Margin for Reporting Segments and Other Operating Results (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information
Total Sales	$ 155,408	$ 241,256	$ 506,877	$ 627,152
Total segment contribution margin	36,488	93,874	136,925	223,364
Operating activities excluded from segment cost of goods sold	(3,679)	(2,315)	(8,500)	(5,096)
Selling, general and administrative	(13,559)	(18,600)	(47,095)	(53,312)
Depreciation, depletion and amortization	(15,158)	(12,425)	(42,096)	(32,355)
Interest expense	(6,684)	(4,950)	(20,448)	(12,771)
Other income, net, including interest income	309	120	818	379
Income/(loss) before income taxes	(2,283)	55,704	19,604	120,209
Operating Segments | Oil & Gas Proppants
Segment Reporting Information
Total Sales	101,987	186,812	341,593	466,727
Total segment contribution margin	16,521	77,030	81,972	175,718
Operating Segments | Industrial & Specialty Products
Segment Reporting Information
Total Sales	53,421	54,444	165,284	160,425
Total segment contribution margin	$ 19,967	$ 16,844	$ 54,953	$ 47,646

Subsequent Events (Details)

Subsequent Events (Details) - USD ($)	Oct. 02, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2015
Subsequent Event
Payable date		Oct. 2, 2015	Jul. 6, 2015	Apr. 3, 2015
Dividends, Common Stock, Cash					$ 20,084,000
Record date		Sep. 15, 2015	Jun. 15, 2015	Mar. 16, 2015
Declaration date		Jul. 24, 2015	May 8, 2015	Feb. 12, 2015
Subsequent Event
Subsequent Event
Dividends, Common Stock, Cash	$ 0.125