Bison Merger Sub I (FMSA) 10-Q 10 May 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	May 08, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Trading Symbol	FMSA
Entity Registrant Name	Fairmount Santrol Holdings Inc.
Entity Central Index Key	1,010,858
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock Shares Outstanding		225,117,303

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income (Loss) (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Revenues	$ 273,338	$ 172,583
Cost of goods sold (excluding depreciation, depletion, and amortization shown separately)	186,078	134,203
Operating expenses
Selling, general and administrative expenses	27,353	22,470
Depreciation, depletion and amortization expense	17,225	17,246
Other operating income	(729)	(1,060)
Income (loss) from operations	43,411	(276)
Interest expense	13,783	12,537
Income (loss) before provision (benefit) for income taxes	29,628	(12,813)
Provision (benefit) for income taxes	872	(1,160)
Net income (loss)	28,756	(11,653)
Less: Net income attributable to the non-controlling interest	3	178
Net income (loss) attributable to Fairmount Santrol Holdings Inc.	$ 28,753	$ (11,831)
Earnings (loss) per share
Basic	$ 0.13	$ (0.05)
Diluted	$ 0.13	$ (0.05)
Weighted average number of shares outstanding
Basic	224,484	223,739
Diluted	228,940	223,739

Condensed Consolidated Stateme3

Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ 28,756	$ (11,653)
Other comprehensive income, before tax
Foreign currency translation	16	(39)
Pension obligations	60	61
Amortization and change in fair value of derivative agreements	1,069	1,613
Total other comprehensive income, before tax	1,145	1,635
Provision for income taxes related to items of other comprehensive income (loss)	538	1,316
Comprehensive income (loss), net of tax	29,363	(11,334)
Comprehensive income attributable to the non-controlling interest	3	178
Comprehensive income (loss) attributable to Fairmount Santrol Holdings Inc.	$ 29,360	$ (11,512)

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 84,768	$ 127,967	$ 210,664	$ 194,069
Accounts receivable, net of allowance for doubtful accounts of $1,237 and $2,003 at March 31, 2018 and December 31, 2017, respectively	179,234	156,916
Inventories, net	64,895	70,528
Prepaid expenses and other assets	7,590	7,765
Total current assets	336,487	363,176
Property, plant and equipment, net	783,429	756,288
Deferred income taxes	351	350
Goodwill	15,301	15,301
Intangibles, net	92,892	93,268
Other assets	10,088	7,711
Total assets	1,238,548	1,236,094
Current liabilities
Current portion of long-term debt	18,924	19,189
Accounts payable	83,852	70,633
Accrued expenses	41,660	74,007
Deferred revenue	9,346	5,660
Total current liabilities	153,782	169,489
Long-term debt	715,316	729,741
Deferred income taxes	6,807	2,429
Other long-term liabilities	36,901	42,189
Total liabilities	912,806	943,848
Commitments and contingent liabilities (Note 14)
Equity
Preferred stock: $0.01 par value, 100,000 authorized shares Shares outstanding: 0 at March 31, 2018 and December 31, 2017
Common stock: $0.01 par value, 1,850,000 authorized shares Shares issued: 242,366 at March 31, 2018 and December 31, 2017 Shares outstanding: 224,895 and 224,291 at March 31, 2018 and December 31, 2017, respectively	2,423	2,423
Additional paid-in capital	294,500	299,912
Retained earnings	318,912	290,159
Accumulated other comprehensive loss	(14,491)	(15,098)
Total equity attributable to Fairmount Santrol Holdings Inc. before treasury stock	601,344	577,396
Less: Treasury stock at cost Shares in treasury: 17,471 and 18,075 at March 31, 2018 and December 31, 2017, respectively	(275,975)	(285,520)
Total equity attributable to Fairmount Santrol Holdings Inc.	325,369	291,876
Non-controlling interest	373	370
Total equity	325,742	292,246	$ 215,568	$ 223,734
Total liabilities and equity	$ 1,238,548	$ 1,236,094

Condensed Consolidated Balance5

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 1,237	$ 2,003
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	100,000,000	100,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	1,850,000,000	1,850,000,000
Common Stock, Shares, Issued	242,366,000	242,366,000
Common stock, shares outstanding	224,895,000	224,291,000
Shares in treasury	17,471,000	18,075,000

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Subtotal [Member]	Non-controlling Interest [Member]
Beginning balances at Dec. 31, 2016	$ 223,734	$ 2,422	$ 297,649	$ 237,466	$ (19,002)	$ (294,874)	$ 223,661	$ 73
Beginning balances, shares at Dec. 31, 2016		223,601				18,666
Re-issuance of treasury stock	4,061					$ 4,061	4,061
Re-issuance of treasury stock, shares		257				(257)
Share-based awards exercised or distributed	(3,575)		(3,575)				(3,575)
Share-based awards exercised or distributed, shares		81
Stock compensation expense	3,116		3,116				3,116
Impact of adoption of ASU 2016-09, net of tax | ASU 2016-09 [Member]	(433)			(433)			(433)
Transactions with non-controlling interest	(1)							(1)
Net (loss) income	(11,653)			(11,831)			(11,831)	178
Other comprehensive income (loss)	319				319		319
Ending balances at Mar. 31, 2017	215,568	$ 2,422	297,190	225,202	(18,683)	$ (290,813)	215,318	250
Ending balances, shares at Mar. 31, 2017		223,939				18,409
Beginning balances at Dec. 31, 2016	223,734	$ 2,422	297,649	237,466	(19,002)	$ (294,874)	223,661	73
Beginning balances, shares at Dec. 31, 2016		223,601				18,666
Ending balances at Dec. 31, 2017	292,246	$ 2,423	299,912	290,159	(15,098)	$ (285,520)	291,876	370
Ending balances, shares at Dec. 31, 2017		224,291				18,075
Re-issuance of treasury stock	9,545					$ 9,545	9,545
Re-issuance of treasury stock, shares		604				(604)
Share-based awards exercised or distributed	(8,832)		(8,832)				(8,832)
Stock compensation expense	3,420		3,420				3,420
Net (loss) income	28,756			28,753			28,753	3
Other comprehensive income (loss)	607				607		607
Ending balances at Mar. 31, 2018	$ 325,742	$ 2,423	$ 294,500	$ 318,912	$ (14,491)	$ (275,975)	$ 325,369	$ 373
Ending balances, shares at Mar. 31, 2018		224,895				17,471

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement Of Cash Flows [Abstract]
Net income (loss)	$ 28,756	$ (11,653)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and depletion	15,198	15,334
Amortization	2,945	3,130
Reserve for doubtful accounts	(764)	(447)
Gain on disposal of fixed assets	(10)	(714)
Gain on interest rate swaps	(99)
Deferred income taxes and taxes payable	3,578	107
Stock compensation expense	3,420	2,416
Change in operating assets and liabilities:
Accounts receivable	(21,554)	(15,956)
Inventories	5,633	(9,038)
Prepaid expenses and other assets	(3,120)	867
Accounts payable	5,613	12,981
Accrued expenses	(33,431)	9,744
Deferred revenue	3,686	16,969
Net cash provided by operating activities	9,851	23,740
Cash flows from investing activities
Proceeds from sale of fixed assets	205	957
Capital expenditures and stripping costs	(37,823)	(4,574)
Net cash used in investing activities	(37,618)	(3,617)
Cash flows from financing activities
Payments on term loans	(4,375)	(2,170)
Payments on capital leases and other long-term debt	(1,163)	(817)
Payments on revolving credit facility	(10,000)
Proceeds from share-based awards exercised or distributed	713	486
Tax payments for withholdings on share-based awards exercised or distributed	(623)	(982)
Transactions with non-controlling interest		(1)
Net cash used in financing activities	(15,448)	(3,484)
Foreign currency adjustment	16	(44)
(Decrease) increase in cash and cash equivalents	(43,199)	16,595
Cash and cash equivalents:
Beginning of period	127,967	194,069
End of period	84,768	210,664
Supplemental disclosure of cash flow information:
Interest paid, net of capitalized interest	14,853	11,717
Income taxes paid (refunded)	375	(1,601)
Non-cash investing activities:
Equipment purchased under capital leases		4,175
Decrease in accounts payable for additions to property, plant, and equipment	$ (7,606)	$ (1,301)

Significant Accounting Policies

Significant Accounting Policies	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Significant Accounting Policies	1. Significant Accounting Policies Basis of Presentation The unaudited condensed consolidated financial statements of Fairmount Santrol Holdings Inc. and its consolidated subsidiaries (collectively, the “Company”) have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, the unaudited condensed consolidated financial statements reflect all adjustments (which are of a normal, recurring nature) and disclosures necessary for a fair statement of the financial position, results of operations, comprehensive income, and cash flows of the reported interim periods. The Condensed Consolidated Balance Sheets as of December 31, 2017 was derived from audited financial statements, but does not include all disclosures required by GAAP. Certain reclassifications of prior year amounts have been made to conform to current year presentation. Interim results are not necessarily indicative of the results to be expected for the full year or any other interim period. These unaudited condensed consolidated financial statements should be read in conjunction with the Company’s consolidated financial statements as filed in the 2017 Annual Report on Form 10-K and notes thereto and information included elsewhere in this Quarterly Report on Form 10-Q. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates. Revisions of Previously-Issued Financial Statements The Company has revised previously-reported results to properly report stripping costs that were previously capitalized when incurred and amortized in subsequent periods. Such costs incurred during the production phase of a mine are variable production costs that should be included in the costs of the inventory produced during the period the stripping costs are incurred. The Company also revised the asset impairment charge for the quarter ended June 30, 2016 to correct its estimated fair value for an impaired mine property included in the determination of the impairment charge. Additionally, the Company has included in the revised statements of cash flows a previously-omitted disclosure to show increase or decrease in accounts payable for additions to property, plant, and equipment. The Company assessed the materiality of these misstatements on prior periods’ financial statements and concluded that these misstatements were not material, individually or in aggregate, to any previously-issued financial statements. Refer to Note 2 for additional information. Revenues The Company derives its revenues by mining, manufacturing, and processing minerals that its customers purchase for various uses. Revenues are measured by the amount of consideration the Company expects to receive in exchange for transferring its product. The consideration the Company expects to receive is based on volumes and price of product as defined in the underlying contract. Depending on the contract, this may include the cost of transportation and may be net of discounts and rebates. In some instances, revenues also include a separate charge for transportation services the Company provides or arranges for customers. On January 1, 2018, the Company adopted Revenue from Contracts with Customers Accounts Receivable – Contract Balances Accounts receivable as presented in the consolidated balance sheets are related to the Company’s contracts and are recorded when the right to consideration becomes unconditional at the amount management expects to collect. Accounts receivable do not bear interest if paid when contractually due, and payments are generally due within thirty to forty-five days of invoicing. Accounts receivable, net of allowance for doubtful accounts, are $179,234 and $156,916 as of March 31, 2018 and December 31, 2017, respectively. The Company typically does not record contract assets, as the transfer of control of its products results in an unconditional right to receive consideration. Deferred Revenues – Contract Balances The Company enters into certain contracts with customers that include provisions requiring receipt of payment at the inception of the contract. Deferred revenue is recorded when payment is received or due in advance of the performance obligation. Changes in deferred revenue were as follows: Three Months Ended March 31, 2018 Beginning balance $ 8,963 Deferral of revenue 5,000 Recognition of unearned revenue (678 ) Ending balance $ 13,285 At March 31, 2018 and December 31, 2017, respectively, deferred revenue balances of $9,346 and $5,660 were recorded as current liabilities. At March 31, 2018 and December 31, 2017, respectively, deferred revenue balances of $3,939 and $3,303 were recorded in other long-term liabilities. Recent Accounting Pronouncements Recently Adopted Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09 – Revenue from Contracts with Customers (Topic 606) Topic 605 – Revenue Recognition On January 1, 2018, the Company adopted the ASU for all contracts which were not completed as of January 1, 2018 using the modified retrospective transition method. The adoption did not require a cumulative adjustment to opening retained earnings and did not have a material impact on revenues for the quarter ended March 31, 2018. See Note 18 for further details. In March 2017, the FASB issued ASU No. 2017-07 – Compensation – Retirement Benefits (Topic 715) – Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost Recently Issued Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02 – Leases (Topic 842) In August 2017, the FASB issued ASU No. 2017-12 – Derivatives and Hedging (Topic 815) – Targeted Improvements to Accounting for Hedging Activities In February 2018, the FASB issued ASU No. 2018-02 – Income Statement – Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income In March 2018, the FASB issued ASU no. 2018-05 – Income Taxes (Topic 740): Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118.

Revisions of Previously-Reporte

Revisions of Previously-Reported Results	3 Months Ended
	Mar. 31, 2018
Accounting Changes And Error Corrections [Abstract]
Revisions of Previously-Issued Financial Statements	2 . Revisions of Previously-Issued Financial Statements The Company has revised previously-reported results to properly report stripping costs that were previously capitalized when incurred and amortized in subsequent periods. Such costs incurred during the production phase of a mine are variable production costs that should be included in the costs of the inventory produced during the period the stripping costs are incurred. The Company also revised the asset impairment charge for the quarter ended June 30, 2016 to correct its estimated fair value for an impaired mine property included in the determination of the impairment charge. Additionally, the Company has included in the revised statements of cash flows a previously-omitted disclosure to show increase or decrease in accounts payable for additions to property, plant, and equipment. The Company assessed the materiality of these misstatements on prior periods’ financial statements in accordance with SEC Staff Accounting Bulletin (“SAB”) No. 99, Materiality Presentation of Financial Statements Considering the Effects of Prior Year Misstatements when Quantifying Misstatements in Current Year Financial Statements The following tables show the impact of these revisions on all of the impacted line items from the Company’s (i) unaudited condensed consolidated financial statements for the three months ended March 31, 2017 and (ii) consolidated financial statements as of December 31, 2017 and 2016, and for the years ended December 31, 2017, 2016, and 2015: Consolidated Statement of Loss Three Months Ended March 31, 2017 As Reported Adjustments As Corrected (in thousands, except per share amounts) Revenues $ 172,583 $ - $ 172,583 Cost of goods sold (excluding depreciation, depletion, and amortization shown separately) 131,752 2,451 134,203 Operating expenses Selling, general and administrative expenses 22,470 - 22,470 Depreciation, depletion and amortization expense 19,442 (2,196 ) 17,246 Other operating (income) expense (1,060 ) - (1,060 ) Income (loss) from operations (21 ) (255 ) (276 ) Interest expense 12,537 - 12,537 Income (loss) before benefit from income taxes (12,558 ) (255 ) (12,813 ) Benefit from income taxes (1,148 ) (12 ) (1,160 ) Net income (loss) (11,410 ) (243 ) (11,653 ) Less: Net income attributable to the non-controlling interest 178 - 178 Net income (loss) attributable to Fairmount Santrol Holdings Inc. $ (11,588 ) $ (243 ) $ (11,831 ) Loss per share Basic $ (0.05 ) $ - $ (0.05 ) Diluted $ (0.05 ) $ - $ (0.05 ) Weighted average number of shares outstanding Basic 223,739 ― 223,739 Diluted 223,739 ― 223,739 Consolidated Statement of Income Year Ended December 31, 2017 As Reported Adjustments As Corrected (in thousands, except per share amounts) Revenues $ 959,795 $ - $ 959,795 Cost of goods sold (excluding depreciation, depletion, and amortization shown separately) 659,758 11,443 671,201 Operating expenses Selling, general and administrative expenses 113,240 - 113,240 Depreciation, depletion and amortization expense 79,144 (9,734 ) 69,410 Other operating income (1,072 ) - (1,072 ) Income from operations 108,725 (1,709 ) 107,016 Interest expense 56,408 - 56,408 Loss on debt extinguishment, net 2,898 - 2,898 Income before benefit from income taxes 49,419 (1,709 ) 47,710 Benefit from income taxes (4,666 ) (1,049 ) (5,715 ) Net income 54,085 (660 ) 53,425 Less: Net income attributable to the non-controlling interest 297 - 297 Net income attributable to Fairmount Santrol Holdings Inc. $ 53,788 $ (660 ) $ 53,128 Earnings per share Basic $ 0.24 $ - $ 0.24 Diluted $ 0.23 $ - $ 0.23 Weighted average number of shares outstanding Basic 223,993 ― 223,993 Diluted 229,084 ― 229,084 Consolidated Statement of Loss Year Ended December 31, 2016 As Reported Adjustments As Corrected (in thousands, except per share amounts) Revenues $ 535,013 $ - $ 535,013 Cost of goods sold (excluding depreciation, depletion, and amortization shown separately) 459,714 9,803 469,517 Operating expenses Selling, general and administrative expenses 79,140 - 79,140 Depreciation, depletion and amortization expense 72,276 (8,962 ) 63,314 Goodwill and other asset impairments 93,148 (3,297 ) 89,851 Restructuring charges 1,155 - 1,155 Other operating expense 8,899 - 8,899 Loss from operations (179,319 ) 2,456 (176,863 ) Interest expense 65,367 - 65,367 Gain on repurchase of debt, net (5,110 ) - (5,110 ) Other non-operating income (10 ) - (10 ) Loss before benefit from income taxes (239,566 ) 2,456 (237,110 ) Benefit from income taxes (99,441 ) 10,811 (88,630 ) Net loss (140,125 ) (8,355 ) (148,480 ) Less: Net income attributable to the non-controlling interest 67 - 67 Net loss attributable to Fairmount Santrol Holdings Inc. $ (140,192 ) $ (8,355 ) $ (148,547 ) Loss per share Basic $ (0.78 ) $ (0.05 ) $ (0.83 ) Diluted $ (0.78 ) $ (0.05 ) $ (0.83 ) Weighted average number of shares outstanding Basic 179,429 ― 179,429 Diluted 179,429 ― 179,429 Consolidated Statement of Loss Year Ended December 31, 2015 As Reported Adjustments As Corrected (in thousands, except per share amounts) Revenues $ 828,709 $ - $ 828,709 Cost of goods sold (excluding depreciation, depletion, and amortization shown separately) 608,845 7,175 616,020 Operating expenses Selling, general and administrative expenses 85,191 - 85,191 Depreciation, depletion and amortization expense 66,754 (6,348 ) 60,406 Goodwill and other asset impairments 87,476 - 87,476 Restructuring charges 9,221 - 9,221 Other operating expense 1,357 (378 ) 979 Loss from operations (30,135 ) (449 ) (30,584 ) Interest expense 62,242 - 62,242 Other non-operating expense 1,492 - 1,492 Loss before benefit from income taxes (93,869 ) (449 ) (94,318 ) Benefit from income taxes (1,939 ) (164 ) (2,103 ) Net loss (91,930 ) (285 ) (92,215 ) Less: Net income attributable to the non-controlling interest 205 - 205 Net loss attributable to Fairmount Santrol Holdings Inc. $ (92,135 ) $ (285 ) $ (92,420 ) Loss per share Basic $ (0.57 ) $ - $ (0.57 ) Diluted $ (0.57 ) $ - $ (0.57 ) Weighted average number of shares outstanding Basic 161,297 ― 161,297 Diluted 161,297 ― 161,297 Consolidated Statement of Comprehensive Loss Three Months Ended March 31, 2017 As Reported Adjustments As Corrected (in thousands) Net loss $ (11,410 ) $ (243 ) $ (11,653 ) Other comprehensive income, before tax Foreign currency translation (39 ) - (39 ) Pension obligations 61 - 61 Change in fair value of derivative agreements 1,613 - 1,613 Total other comprehensive income, before tax 1,635 - 1,635 Provision for income taxes related to items of other comprehensive income 1,316 - 1,316 Comprehensive loss, net of tax (11,091 ) (243 ) (11,334 ) Comprehensive income attributable to the non-controlling interest 178 - 178 Comprehensive loss attributable to Fairmount Santrol Holdings Inc. $ (11,269 ) $ (243 ) $ (11,512 ) Consolidated Statement of Comprehensive Income Year Ended December 31, 2017 As Reported Adjustments As Corrected (in thousands) Net income $ 54,085 $ (660 ) $ 53,425 Other comprehensive income, before tax Foreign currency translation 555 - 555 Pension obligations 336 - 336 Change in fair value of derivative agreements 5,863 - 5,863 Total other comprehensive income, before tax 6,754 - 6,754 Provision for income taxes related to items of other comprehensive income 2,850 - 2,850 Comprehensive income, net of tax 57,989 (660 ) 57,329 Comprehensive income attributable to the non-controlling interest 297 - 297 Comprehensive income attributable to Fairmount Santrol Holdings Inc. $ 57,692 $ (660 ) $ 57,032 Consolidated Statement of Comprehensive Loss Year Ended December 31, 2016 As Reported Adjustments As Corrected (in thousands) Net loss $ (140,125 ) $ (8,355 ) $ (148,480 ) Other comprehensive loss, before tax Foreign currency translation (774 ) - (774 ) Pension obligations 425 - 425 Change in fair value of derivative agreements (3,018 ) - (3,018 ) Total other comprehensive loss, before tax (3,367 ) - (3,367 ) Benefit from income taxes related to items of other comprehensive loss (2,058 ) - (2,058 ) Comprehensive loss, net of tax (141,434 ) (8,355 ) (149,789 ) Comprehensive income attributable to the non-controlling interest 67 - 67 Comprehensive loss attributable to Fairmount Santrol Holdings Inc. $ (141,501 ) $ (8,355 ) $ (149,856 ) Consolidated Statement of Comprehensive Loss Year Ended December 31, 2015 As Reported Adjustments As Corrected (in thousands) Net loss $ (91,930 ) $ (285 ) $ (92,215 ) Other comprehensive loss, before tax Foreign currency translation (5,051 ) - (5,051 ) Pension obligations 222 - 222 Change in fair value of derivative agreements (1,836 ) - (1,836 ) Total other comprehensive loss, before tax (6,665 ) - (6,665 ) Benefit from income taxes related to items of other comprehensive loss (1,780 ) - (1,780 ) Comprehensive loss, net of tax (96,815 ) (285 ) (97,100 ) Comprehensive income attributable to the non-controlling interest 205 - 205 Comprehensive loss attributable to Fairmount Santrol Holdings Inc. $ (97,020 ) $ (285 ) $ (97,305 ) Consolidated Balance Sheet December 31, 2017 As Reported Adjustments As Corrected (in thousands) Assets Current assets Cash and cash equivalents $ 127,967 $ - $ 127,967 Accounts receivable, net of allowance for doubtful accounts of $2,003 at December 31, 2017 156,916 - 156,916 Inventories, net 70,528 - 70,528 Prepaid expenses and other assets 6,841 - 6,841 Refundable income taxes 924 - 924 Total current assets 363,176 - 363,176 Property, plant and equipment, net 785,513 (29,225 ) 756,288 Deferred income taxes 350 - 350 Goodwill 15,301 - 15,301 Intangibles, net 93,268 - 93,268 Other assets 7,711 - 7,711 Total assets $ 1,265,319 $ (29,225 ) $ 1,236,094 Liabilities and Equity Current liabilities Current portion of long-term debt $ 19,189 $ - $ 19,189 Accounts payable 70,633 - 70,633 Accrued expenses 74,007 - 74,007 Deferred revenue 5,660 - 5,660 Total current liabilities 169,489 - 169,489 Long-term debt 729,741 - 729,741 Deferred income taxes 3,606 (1,177 ) 2,429 Other long-term liabilities 42,189 - 42,189 Total liabilities 945,025 (1,177 ) 943,848 Commitments and contingent liabilities Equity Preferred stock: $0.01 par value, 100,000 authorized shares Shares outstanding: 0 at December 31, 2017 - - - Common stock: $0.01 par value, 1,850,000 authorized shares Shares issued: 242,366 at December 31, 2017 Shares outstanding: 224,291 at December 31, 2017 2,423 - 2,423 Additional paid-in capital 299,912 - 299,912 Retained earnings 318,207 (28,048 ) 290,159 Accumulated other comprehensive loss (15,098 ) - (15,098 ) Total equity attributable to Fairmount Santrol Holdings Inc. before treasury stock 605,444 (28,048 ) 577,396 Less: Treasury stock at cost Shares in treasury: 18,075 at December 31, 2017 (285,520 ) - (285,520 ) Total equity attributable to Fairmount Santrol Holdings Inc. 319,924 (28,048 ) 291,876 Non-controlling interest 370 - 370 Total equity 320,294 (28,048 ) 292,246 Total liabilities and equity $ 1,265,319 $ (29,225 ) $ 1,236,094 Consolidated Balance Sheet December 31, 2016 As Reported Adjustments As Corrected (in thousands) Assets Current assets Cash and cash equivalents $ 194,069 $ - $ 194,069 Accounts receivable, net of allowance for doubtful accounts of $3,055 at December 31, 2016 78,942 - 78,942 Inventories, net 52,650 - 52,650 Prepaid expenses and other assets 7,065 - 7,065 Refundable income taxes 21,077 - 21,077 Total current assets 353,803 - 353,803 Property, plant and equipment, net 727,735 (27,514 ) 700,221 Deferred income taxes 1,244 - 1,244 Goodwill 15,301 - 15,301 Intangibles, net 95,341 - 95,341 Other assets 9,486 - 9,486 Total assets $ 1,202,910 $ (27,514 ) $ 1,175,396 Liabilities and Equity Current liabilities Current portion of long-term debt $ 10,707 $ - $ 10,707 Accounts payable 37,263 - 37,263 Accrued expenses 26,110 - 26,110 Deferred revenue 75 - 75 Total current liabilities 74,155 - 74,155 Long-term debt 832,306 - 832,306 Deferred income taxes 7,057 (128 ) 6,929 Other long-term liabilities 38,272 - 38,272 Total liabilities 951,790 (128 ) 951,662 Commitments and contingent liabilities Equity Preferred stock: $0.01 par value, 100,000 authorized shares Shares outstanding: 0 at December 31, 2016 - - - Common stock: $0.01 par value, 1,850,000 authorized shares Shares issued: 242,267 at December 31, 2016 Shares outstanding: 223,601 at December 31, 2016 2,422 - 2,422 Additional paid-in capital 297,649 - 297,649 Retained earnings 264,852 (27,386 ) 237,466 Accumulated other comprehensive loss (19,002 ) - (19,002 ) Total equity attributable to Fairmount Santrol Holdings Inc. before treasury stock 545,921 (27,386 ) 518,535 Less: Treasury stock at cost Shares in treasury: 18,666 at December 31, 2016 (294,874 ) - (294,874 ) Total equity attributable to Fairmount Santrol Holdings Inc. 251,047 (27,386 ) 223,661 Non-controlling interest 73 - 73 Total equity 251,120 (27,386 ) 223,734 Total liabilities and equity $ 1,202,910 $ (27,514 ) $ 1,175,396 Consolidated Statement of Cash Flows Three Months Ended March 31, 2017 As Reported Adjustments As Corrected (in thousands) Net loss $ (11,410 ) $ (243 ) $ (11,653 ) Adjustments to reconcile net loss to net cash provided by operating activities: Depreciation and depletion 17,530 (2,196 ) 15,334 Amortization 3,130 - 3,130 Reserve for doubtful accounts (447 ) - (447 ) Gain on disposal of fixed assets (714 ) - (714 ) Deferred income taxes and taxes payable 119 (12 ) 107 Stock compensation expense 2,416 - 2,416 Change in operating assets and liabilities: Accounts receivable (15,956 ) - (15,956 ) Inventories (9,038 ) - (9,038 ) Prepaid expenses and other assets (1,078 ) 1,945 867 Refundable income taxes 1,945 (1,945 ) - Accounts payable 12,981 - 12,981 Accrued expenses and deferred revenue 26,489 (26,489 ) - Accrued expenses - 9,744 9,744 Deferred revenue - 16,969 16,969 Net cash provided by operating activities 25,967 (2,227 ) 23,740 Cash flows from investing activities Proceeds from sale of fixed assets 957 - 957 Capital expenditures and stripping costs (7,025 ) 2,451 (4,574 ) Other investing activities (758 ) 758 - Net cash used in investing activities (6,826 ) 3,209 (3,617 ) Cash flows from financing activities Payments on term loans (2,170 ) - (2,170 ) Payments on capital leases and other long-term debt (817 ) - (817 ) Proceeds from share-based awards exercised or distributed 486 - 486 Tax payments for withholdings on share-based awards exercised or distributed - (982 ) (982 ) Transactions with non-controlling interest (1 ) - (1 ) Net cash used in financing activities (2,502 ) (982 ) (3,484 ) Foreign currency adjustment (44 ) - (44 ) Increase in cash and cash equivalents 16,595 - 16,595 Cash and cash equivalents: Beginning of period 194,069 - 194,069 End of period $ 210,664 $ - $ 210,664 Supplemental disclosure of cash flow information: Interest paid, net of capitalized interest $ 11,717 Income taxes refunded (1,601 ) Non-cash investing activities: Equipment purchased under capital leases $ 4,175 Decrease in accounts payable for additions to property, plant, and equipment (1,301 ) Consolidated Statement of Cash Flows Year Ended December 31, 2017 As Reported Adjustments As Corrected (in thousands) Net income $ 54,085 $ (660 ) $ 53,425 Adjustments to reconcile net income to net cash provided by operating activities: Depreciation and depletion 71,397 (9,734 ) 61,663 Amortization 12,784 - 12,784 Reserve for doubtful accounts (387 ) - (387 ) Write-off of deferred financing costs 389 - 389 Loss on debt extinguishment, gross 2,898 - 2,898 Inventory write-downs and reserves 1,266 - 1,266 Loss on disposal of fixed assets 846 - 846 Unrealized loss on interest rate swaps 14 - 14 Deferred income taxes and taxes payable (5,634 ) (1,049 ) (6,683 ) Stock compensation expense 10,071 - 10,071 Change in operating assets and liabilities: Accounts receivable (77,587 ) - (77,587 ) Inventories (19,144 ) - (19,144 ) Prepaid expenses and other assets (2,398 ) - (2,398 ) Refundable income taxes 20,154 - 20,154 Accounts payable 18,575 - 18,575 Accrued expenses 51,874 - 51,874 Deferred revenue 5,585 - 5,585 Net cash provided by operating activities 144,788 (11,443 ) 133,345 Cash flows from investing activities Proceeds from sale of fixed assets 4,939 - 4,939 Capital expenditures and stripping costs (69,573 ) 11,443 (58,130 ) Leasehold interest payments for sand reserves (30,000 ) - (30,000 ) Earnout payments (4,170 ) - (4,170 ) Net cash used in investing activities (98,804 ) 11,443 (87,361 ) Cash flows from financing activities Proceeds from borrowings on term loan 689,500 - 689,500 Payments on term loans (6,469 ) - (6,469 ) Prepayments on term loans (832,655 ) - (832,655 ) Fees for debt restructure and repurchase of term loans (2,790 ) - (2,790 ) Payments on capital leases and other long-term debt (4,752 ) - (4,752 ) Proceeds from borrowing on revolving credit facility 50,000 - 50,000 Payments on revolving credit facility (5,000 ) - (5,000 ) Proceeds from option exercises 845 - 845 Tax payments for withholdings on share-based awards exercised or distributed (1,321 ) - (1,321 ) Net cash used in financing activities (112,642 ) - (112,642 ) Foreign currency adjustment 556 - 556 Decrease in cash and cash equivalents (66,102 ) - (66,102 ) Cash and cash equivalents: Beginning of period 194,069 - 194,069 End of period $ 127,967 $ - $ 127,967 Supplemental disclosure of cash flow information: Interest paid, net of capitalized interest $ 59,498 Income taxes refunded (19,278 ) Non-cash investing activities: Equipment purchased under capital leases $ 10,988 Decrease in accounts payable for additions to property, plant, and equipment (14,796 ) Consolidated Statement of Cash Flows Year Ended December 31, 2016 As Reported Adjustments As Corrected (in thousands) Net loss $ (140,125 ) $ (8,355 ) $ (148,480 ) Adjustments to reconcile net loss to net cash provided by (used in) operating activities: Depreciation and depletion 67,614 (8,962 ) 58,652 Amortization 11,641 - 11,641 Reserve for doubtful accounts 1,851 - 1,851 Write-off of deferred financing costs 2,618 - 2,618 Gain on repurchase of debt, gross (8,178 ) - (8,178 ) Goodwill and other asset impairments 93,148 (3,297 ) 89,851 Inventory write-downs and reserves 10,302 - 10,302 Loss on disposal of fixed assets 420 - 420 Deferred income taxes and taxes payable (82,732 ) 10,811 (71,921 ) Stock compensation expense 8,870 - 8,870 Change in operating assets and liabilities: Accounts receivable (4,385 ) - (4,385 ) Inventories 7,543 - 7,543 Prepaid expenses and other assets 11,496 - 11,496 Refundable income taxes 5,428 - 5,428 Accounts payable 4,196 - 4,196 Accrued expenses 11,718 - 11,718 Deferred revenue 75 - 75 Net cash provided by (used in) operating activities 1,500 (9,803 ) (8,303 ) Cash flows from investing activities Proceeds from sale of fixed assets 5,670 - 5,670 Capital expenditures and stripping costs (30,597 ) 9,803 (20,794 ) Earnout payments (1,287 ) - (1,287 ) Net cash used in investing activities (26,214 ) 9,803 (16,411 ) Cash flows from financing activities Payments on term loans (10,840 ) - (10,840 ) Prepayments on term loans (155,926 ) - (155,926 ) Repurchase of term loans (216,000 ) - (216,000 ) Fees for debt restructure and repurchase of term loans (450 ) - (450 ) Payments on capital leases and other long-term debt (5,947 ) - (5,947 ) Proceeds from option exercises 6,438 - 6,438 Proceeds from primary stock offering 439,556 - 439,556 Tax payments for withholdings on share-based awards exercised or distributed (8,092 ) - (8,092 ) Tax effect of share-based awards exercised, forfeited, or expired (1,100 ) - (1,100 ) Transactions with non-controlling interest (842 ) - (842 ) Net cash provided by financing activities 46,797 - 46,797 Change in cash and cash equivalents related to assets classified as held-for-sale 1,376 - 1,376 Foreign currency adjustment (876 ) - (876 ) Increase in cash and cash equivalents 22,583 - 22,583 Cash and cash equivalents: Beginning of period 171,486 - 171,486 End of period $ 194,069 $ - $ 194,069 Supplemental disclosure of cash flow information: Interest paid, net of capitalized interest $ 60,833 Income taxes refunded (21,311 ) Non-cash investing activities: Equipment purchased under capital leases $ - Increase in accounts payable for additions to property, plant, and equipment 8,100 Consolidated Statement of Cash Flows Year Ended December 31, 2015 As Reported Adjustments As Corrected (in thousands) Net loss $ (91,930 ) $ (285 ) $ (92,215 ) Adjustments to reconcile net loss to net cash provided by operating activities: Depreciation and depletion 62,218 (6,348 ) 55,870 Amortization 11,416 - 11,416 Reserve for doubtful accounts 1,968 - 1,968 Write-off of deferred financing costs 864 - 864 Goodwill and other asset impairments 76,038 - 76,038 Non-cash restructuring charges 1,162 - 1,162 Inventory write-downs and reserves 1,591 - 1,591 Loss on disposal of fixed assets 8,712 - 8,712 Unrealized loss on interest rate swaps 49 - 49 Deferred income taxes and taxes payable 20,983 (164 ) 20,819 Stock compensation expense 4,525 - 4,525 Change in operating assets and liabilities: Accounts receivable 127,718 - 127,718 Inventories 59,527 - 59,527 Prepaid expenses and other assets 23,234 - 23,234 Refundable income taxes (26,506 ) - (26,506 ) Accounts payable (38,698 ) - (38,698 ) Accrued expenses (6,051 ) - (6,051 ) Net cash provided by operating activities 236,820 (6,797 ) 230,023 Cash flows from investing activities Capital expenditures and stripping costs (113,750 ) 6,797 (106,953 ) Other investing activities (250 ) - (250 ) Net cash used in investing activities (114,000 ) 6,797 (107,203 ) Cash flows from financing activities Payments on term loans (13,532 ) - (13,532 ) Payments on capital leases and other long-term debt (6,975 ) - (6,975 ) Proceeds from option exercises 1,767 - 1,767 Tax payments for withholdings on share-based awards exercised or distributed (826 ) - (826 ) Tax effect of share-based awards exercised, forfeited, or expired (1,472 ) - (1,472 ) Transactions with non-controlling interest (301 ) - (301 ) Other financing activities (4,578 ) - (4,578 ) Net cash used in financing activities (25,917 ) - (25,917 ) Change in cash and cash equivalents related to assets classified as held-for-sale (1,376 ) - (1,376 ) Foreign currency adjustment (964 ) - (964 ) Increase in cash and cash equivalents 94,563 - 94,563 Cash and cash equivalents: Beginning of period 76,923 - 76,923 End of period $ 171,486 $ - $ 171,486 Supplemental disclosure of cash flow information: Interest paid, net of capitalized interest $ 61,395 Income taxes refunded (19,898 ) Non-cash investing activities: Equipment purchased under capital leases $ 4,552 Increase in accounts payable for additions to property, plant, and equipment 652

Inventories, net

Inventories, net	3 Months Ended
	Mar. 31, 2018
Inventory Disclosure [Abstract]
Inventories, net	3 . Inventories, net At March 31, 2018 and December 31, 2017, inventories consisted of the following: March 31, 2018 December 31, 2017 Raw materials $ 8,368 $ 7,412 Work-in-process 10,303 14,819 Finished goods 46,848 48,931 65,519 71,162 Less: LIFO reserve (624 ) (634 ) Inventories, net $ 64,895 $ 70,528

Property, Plant, and Equipment,

Property, Plant, and Equipment, net	3 Months Ended
	Mar. 31, 2018
Property Plant And Equipment [Abstract]
Property, Plant, and Equipment, net	4 . Property, Plant, and Equipment, net At March 31, 2018 and December 31, 2017, property, plant, and equipment consisted of the following: March 31, 2018 December 31, 2017 Land and improvements $ 83,491 $ 85,012 Mineral reserves and mine development 228,356 222,271 Machinery and equipment 601,745 590,584 Buildings and improvements 186,631 186,466 Furniture, fixtures, and other 3,492 3,478 Construction in progress 81,125 54,661 1,184,840 1,142,472 Accumulated depletion and depreciation (401,411 ) (386,184 ) Property, plant, and equipment, net $ 783,429 $ 756,288 On July 18, 2017, the Company entered into a 40-year lease agreement for approximately 3,250 acres of sand reserves in Kermit, Texas. The Company has capitalized the entire $40,000 leasehold interest obligation and related exploratory and transaction costs to mineral reserves and mine development. The initial payment of $20,000 was paid at lease commencement. An additional $10,000 was paid in October 2017 upon the issuance of all federal, state, and local permits. The remaining $10,000 is payable upon the earlier of two years from the commencement date of the agreement or the date the Company makes its first sale of sand from this property, which the Company expects to be in the second quarter of 2018. The capitalized leasehold interest payments will begin to be recognized as expense as production occurs. Additionally, the Company is obligated for certain royalty payments based on volumes sold.

Long-Term Debt

Long-Term Debt	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Long-Term Debt	5 . Long-Term Debt At March 31, 2018 and December 31, 2017, long-term debt consisted of the following: March 31, 2018 December 31, 2017 Term Loan B $ 685,184 $ 688,990 Industrial Revenue Bond 10,000 10,000 ABL Revolver, Revolving Credit Facility, and other 35,056 45,073 Capital leases, net 8,738 9,884 Deferred financing costs, net (4,738 ) (5,017 ) 734,240 748,930 Less: current portion (18,924 ) (19,189 ) Long-term debt including leases $ 715,316 $ 729,741 On November 1, 2017 (the “Closing Date”), the Company entered into a new five-year asset-based revolving credit facility (the “ABL Revolver”) with PNC Capital Markets LLC, as administrative agent, which replaced the existing revolving credit facility. The ABL Revolver has a borrowing capacity of up to $125,000 with an option to increase by $50,000 to $175,000. An initial draw of $50,000 upon closing of the ABL Revolver was used to partially refinance existing term debt, pay expenses associated with debt refinancing, and can be later used for funding capital expenditures, and providing ongoing working capital. The ABL Revolver is interest only at a rate derived from LIBOR plus 1.5% to 2.0% (depending on excess availability under the ABL Revolver) or from a Base Rate, which is the higher of the prime rate, the Federal Funds open rate plus 0.5% and the Daily LIBOR Rate plus 1.0%. The interest payments on the ABL Revolver are payable in quarterly installments, with the principal balance due at November 1, 2022. If the Term Loan B is still outstanding, then any balance outstanding under the ABL Revolver is due on May 1, 2022. Availability under the ABL Revolver is based upon an available borrowing base, which includes a specified percentage of eligible accounts receivable and inventory and excludes outstanding letters of credit and applicable reserves. In addition to interest charged on the ABL Revolver, the Company is also obligated to pay certain fees, quarterly in arrears, including letter of credit fees and unused facility fees. The ABL Revolver includes financial covenants requiring a minimum fixed charge coverage ratio of 1.1, based on availability thresholds, and is primarily secured by all accounts receivable and inventory, with security interest second to the Term Loan B on substantially all other assets of the Company. Additionally, on the Closing Date, the Company entered into an agreement with Barclays Capital Inc., as administrative agent, for a $700,000 Senior Secured Term Loan (the “Term Loan B”) to refinance all of its existing Term B-2 Loans and Extended Term B-1 Loans. The Term Loan B was issued with original issue discount at 98.5% of face. The Term Loan B, which has a maturity date of November 1, 2022, requires quarterly interest payments and 2.5% annual principal amortization payments for the first half of the loan period, 5.0% for the second half of the loan period, with the balance payable at the maturity date. Interest accrues at the rate of the three-month LIBOR plus 6.0% with a LIBOR floor of 1.0%. The Term Loan B is secured by a first priority security interest in substantially all assets of the Company and its subsidiaries, except for accounts receivable and inventory, in which it has a second priority security interest. The Company has the option to prepay the Term Loan B. Should the Company choose to refinance the Term Loan B, it would be subject to a 1.02% premium if refinanced at a lower interest rate within one year of the Closing Date or a 1.01% premium if refinanced at a lower interest rate within two years of the Closing Date. In the event of a change in control of 35% or more of the voting interests of the Company and at the request of the lenders, the unpaid principal and interest of the Term Loan B may become immediately due and payable. There are no financial covenants governing the Term Loan B. As of March 31, 2018, the Term Loan B and the ABL Revolver had actual interest rates of 8.3% and 3.6%, respectively. As of December 31, 2017, the Term Loan B and the ABL Revolver had actual interest rates of 7.7% and 3.3%, respectively. As of March 31, 2018, the Company was in compliance with all covenants in accordance with the ABL Revolver. As of March 31, 2018, there was $90,000 available unused capacity on the ABL Revolver, $15,290 committed to outstanding letters of credit, and $611 withheld for collateral, leaving net availability at $74,099. The Company has a $10,000 Industrial Revenue Bond outstanding related to the construction of a mining facility in Wisconsin. The bond bears interest, which is payable monthly, at a variable rate. The rate was 1.65% and 1.46% at March 31, 2018 and December 31, 2017, respectively. The bond matures on September 1, 2027 and is collateralized by a letter of credit of $10,000.

Accrued Expenses

Accrued Expenses	3 Months Ended
	Mar. 31, 2018
Payables And Accruals [Abstract]
Accrued Expenses	6 . Accrued Expenses At March 31, 2018 and December 31, 2017, accrued expenses consisted of the following: March 31, 2018 December 31, 2017 Accrued payroll and fringe benefits $ 8,526 $ 11,233 Accrued bonus 3,543 37,166 Accrued income taxes 386 504 Accrued real estate taxes 4,617 5,098 Accrued leasehold interest payments 10,000 10,000 Other accrued expenses 14,588 10,006 Accrued expenses $ 41,660 $ 74,007

Earnings (Loss) per Share

Earnings (Loss) per Share	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Earnings (Loss) per Share	7 . Earnings (Loss) per Share The table below shows the computation of basic and diluted earnings (loss) per share for the three months ended March 31, 2018 and 2017, respectively: Three Months Ended March 31, 2018 2017 Numerator: Net income (loss) attributable to Fairmount Santrol Holdings Inc. $ 28,753 $ (11,831 ) Denominator: Basic weighted average shares outstanding 224,484 223,739 Dilutive effect of employee stock options, RSUs, and PRSUs 4,456 - Diluted weighted average shares outstanding 228,940 223,739 Earnings (loss) per common share – basic $ 0.13 $ (0.05 ) Earnings (loss) per common share – diluted $ 0.13 $ (0.05 ) The calculation of diluted weighted average shares outstanding for the three months ended March 31, 2018 excludes 6,170 potential common shares because the effect of including these potential common shares would be antidilutive. Potentially dilutive shares of 4,739 were excluded from the calculation of diluted weighted average shares outstanding and diluted earnings per share in the three months ended March 31, 2017 because the Company was in a loss position in that period.

Derivative Instruments

Derivative Instruments	3 Months Ended
	Mar. 31, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative Instruments	8 . Derivative Instruments The Company enters into interest rate swap agreements as a means to partially hedge its variable interest rate risk on debt instruments. At March 31, 2018, the Company had one outstanding interest rate swap agreement. The notional value of this swap agreement as of March 31, 2018 and December 31, 2017 is $210,000 and represents approximately 30% of term debt outstanding at March 31, 2018 and December 31, 2017. The swap agreement terminates on September 5, 2019 and effectively fixes the variable rate to 2.92% for the portion of the debt that is hedged. The derivative instruments are recorded on the balance sheet at their fair values. Changes in the fair value of derivatives are recorded each period in current earnings or in other comprehensive income, depending on whether a derivative is designated and qualifying as part of a hedging relationship and, if it is, depending on the type of hedging relationship. The Company recognizes changes in fair value for derivatives not qualifying for hedge accounting in current period earnings. In the event an interest rate swap is terminated prior to maturity, gains or losses in accumulated other comprehensive loss remain deferred and are reclassified into earnings in the periods in which the hedged forecasted transaction affects earnings. The Company formally designates and documents instruments at inception that qualify for hedge accounting of underlying exposures in accordance with GAAP. Both at inception and for each reporting period, the Company assesses whether the financial instruments used in hedging transactions are effective in offsetting changes in cash flows of the related underlying exposure. In December 2017, the Company determined that the existing swap agreement, which previously qualified for hedge accounting treatment, no longer qualified for hedge accounting, as the underlying transaction was no longer probable of occurring. No gain or loss was recognized and the remaining balance of accumulated other comprehensive loss associated with the swap agreement will be amortized into interest expense until September 2019, the date of the expected swap maturity. In November 2017, a swap agreement with a notional value of $210,000 was terminated. Upon termination, the remaining balance in accumulated other comprehensive loss associated with the swap agreement will continue to be amortized and recorded as interest expense until September 2019, the date of the original expected swap maturity. The following table summarizes the fair values and the respective classification in the Condensed Consolidated Balance Sheets as of March 31, 2018 and December 31, 2017: Assets (Liabilities) Interest Rate Swap Agreements Balance Sheet Classification March 31, 2018 December 31, 2017 Non-qualifying cash flow hedge Other long-term liabilities $ (1,394 ) $ (3,208 ) $ (1,394 ) $ (3,208 ) The Company recognized in interest expense the following in the three months ended March 31, 2018 and 2017, respectively, in order to represent the ineffective portion of interest rate swap agreements designated as hedges and interest rate swap agreements no longer qualifying for hedge accounting treatment: Derivatives Designated as Location of (Gain) Loss ASC 815-20 Cash Flow Recognized in Income on Three Months Ended March 31, Hedging Relationships Derivative (Ineffective Portion) 2018 2017 Interest rate swap agreements Interest expense $ - $ (77 ) $ - $ (77 ) Derivatives Not Designated as ASC 815-20 Cash Flow Location of (Gain) Loss Three Months Ended March 31, Hedging Relationships Recognized in Income on Derivative 2018 2017 Interest rate swap agreements Interest expense $ (99 ) $ - $ (99 ) $ - The Company currently expects $4,333 to be reclassified from accumulated other comprehensive loss into interest expense within the next twelve months.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	9 . Fair Value Measurements Financial instruments held by the Company include cash equivalents, accounts receivable, accounts payable, long-term debt (including the current portion thereof) and interest rate swaps. The Company is also liable for contingent consideration from the acquisition of Self-Suspending Proppant LLC (“SSP”) that is subject to fair value measurement. Fair value is defined as the price that would be received to sell an asset, or paid to transfer a liability, in an orderly transaction between market participants at the measurement date. In determining fair value, the Company utilizes certain assumptions that market participants would use in pricing the asset or liability, including assumptions about risk and/or the risks inherent in the inputs to the valuation technique. Based on the examination of the inputs used in the valuation techniques, the Company is required to provide the following information according to the fair value hierarchy. The fair value hierarchy ranks the quality and reliability of the information used to determine fair values. Financial assets and liabilities at fair value will be classified and disclosed in one of the following three categories: Level 1 Quoted market prices in active markets for identical assets or liabilities Level 2 Observable market based inputs or unobservable inputs that are corroborated by market data Level 3 Unobservable inputs that are not corroborated by market data A financial instrument’s categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The carrying value of cash equivalents, accounts receivable, and accounts payable are considered to be representative of their fair values because of their short maturities. The carrying value of SSP approximates the fair value. The carrying value of the Company’s long-term debt (including the current portion thereof) is recognized at amortized cost. The carrying value of the ABL Revolver approximates fair value because its interest rate approximates the current rates available to the Company. The fair value of the Term Loan B differs from amortized cost and is valued at prices obtained from a readily-available source for trading non-public debt, which represent quoted prices for identical or similar assets in markets that are not active, and therefore is considered Level 2. The following table presents the fair value as of March 31, 2018 and December 31, 2017, respectively, for the Company’s long-term debt: Quoted Other in Active Observable Unobservable Markets Inputs Inputs Long-Term Debt Fair Value Measurements (Level 1) (Level 2) (Level 3) Total March 31, 2018 Term Loan B $ - $ 704,320 $ - $ 704,320 $ - $ 704,320 $ - $ 704,320 December 31, 2017 Term Loan B $ - $ 708,750 $ - $ 708,750 $ - $ 708,750 $ - $ 708,750 The following table presents the amounts carried at fair value as of March 31, 2018 and December 31, 2017 for the Company’s other financial instruments. Fair value of interest rate swap agreements is based on the present value of the expected future cash flows, considering the risks involved, and using discount rates appropriate for the maturity date. These are determined using Level 2 inputs. Quoted Other in Active Observable Unobservable Markets Inputs Inputs Recurring Fair Value Measurements (Level 1) (Level 2) (Level 3) Total March 31, 2018 Interest rate swap agreements $ - $ (1,394 ) $ - $ (1,394 ) $ - $ (1,394 ) $ - $ (1,394 ) December 31, 2017 Interest rate swap agreements $ - $ (3,208 ) $ - $ (3,208 ) $ - $ (3,208 ) $ - $ (3,208 )

Common Stock and Stock-Based Co

Common Stock and Stock-Based Compensation	3 Months Ended
	Mar. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Common Stock and Stock-Based Compensation	10 . Common Stock and Stock-Based Compensation In the three months ended March 31, 2018, the Company did not grant any options to purchase shares of common stock and did not issue any performance restricted stock units (“PRSUs”). The Company granted options to purchase 443 shares of common stock in the three months ended March 31, 2017. The average grant date fair value was $10.03 for options issued in the three months ended March 31, 2017. The Company issued restricted stock units (“RSUs”) of 1,581 and 366 in the three months ended March 31, 2018 and 2017, respectively. The Company issued PRSUs of 139 in the three months ended March 31, 2017. Weighted Weighted Performance Weighted Average Exercise Restricted Average Price at Restricted Average Price at Options Price, Options Stock Units RSU Issue Date Stock Units PRSU Issue Date Outstanding at December 31, 2017 13,393 $ 6.63 1,517 $ 6.63 584 $ 4.10 Granted - - 1,581 4.56 - - Exercised (355 ) 2.58 (280 ) 4.65 - - Forfeited (9 ) 10.70 (6 ) 10.03 - - Expired (4 ) 16.00 - - - - Outstanding at March 31, 2018 13,025 $ 6.73 2,812 $ 5.67 584 $ 4.10 The Company recorded $3,420 and $2,416 of stock compensation expense related to these options, RSUs, and PRSUs for the three months ended March 31, 2018 and 2017, respectively. Stock compensation expense is included in selling, general, and administrative expenses on the Condensed Consolidated Statements of Income (Loss) and in additional paid-in capital on the Condensed Consolidated Balance Sheets.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	1 1 . Income Taxes The Company computes and applies to ordinary income an estimated annual effective tax rate on a quarterly basis based on current and forecasted business levels and activities, including the mix of domestic and foreign results and enacted tax laws. The estimated annual effective tax rate is updated quarterly based on actual results and updated operating forecasts. Ordinary income refers to income (loss) before income tax expense excluding significant, unusual, or infrequently occurring items. The tax effect of an unusual or infrequently occurring item is recorded in the interim period in which it occurs as a discrete item of tax. For the three months ended March 31, 2018, the Company recorded tax expense of $872 on income before income taxes of $29,628 resulting in an effective tax rate of 2.9%, compared to a tax benefit of $1,160 on a loss before income taxes of $12,813 resulting in an effective tax rate of 9.1% for the same period of 2017. The decrease in the effective tax rate is primarily attributable to the decrease in the corporate income tax rate to 21% resulting from the Tax Act passed by the United States Government in December 2017. The decrease was partially offset by the reduced impact of the U.S. depletion deduction applied against forecasted results in 2018 as compared to 2017. The effective rate differs from the U.S. federal statutory rate due primarily to depletion and the valuation allowance against certain U.S. tax attributes. The Tax Act subjects U.S. taxpayers to the base erosion minimum tax ("BEAT"), a potential limitation on U.S. interest deduction ("163(j)"), a potential tax deduction for foreign derived intangible income ("FDII"), and a current tax on its global intangible low-taxed income ("GILTI"). The Company estimates that the effect from the BEAT, 163(j), FDII and GILTI on its estimated annual effective tax rate will not be material. For the three months ended March 31, 2018, the Company remains provisional for legislative changes of the Tax Act, most notably for the one-time transition tax on unremitted foreign earnings of $3,046. While substantially complete for which a reasonable estimate of such effects have been recorded, these estimates remain provisional as certain items may differ, potentially materially, due to further refinement of the calculations, changes in interpretations and assumptions made, and further guidance that may become available. The SEC has provided up to a one-year measurement period, ending December 22, 2018, for the Company to finalize the accounting for the impacts of the Tax Act.

Defined Benefit Plans

Defined Benefit Plans	3 Months Ended
	Mar. 31, 2018
Compensation And Retirement Disclosure [Abstract]
Defined Benefit Plans	1 2 . Defined Benefit Plans The Company maintains two defined benefit pension plans, the Wedron pension plan and the Troy Grove pension plan, covering union employees at certain facilities that provide benefits based upon years of service or a combination of employee earnings and length of service. Benefits under the Wedron plan were frozen effective December 31, 2012. Benefits under the Troy Grove plan were frozen effective December 31, 2016. Net periodic benefit (income) cost recognized for Company defined benefit pension plans for the three months ended March 31, 2018 and 2017 is as follows: Three Months Ended March 31, 2018 2017 Components of net periodic benefit (income) cost Interest cost 84 89 Expected return on plan assets (141 ) (127 ) Amortization of net actuarial loss 56 61 Net periodic benefit (income) cost $ (1 ) $ 23 The Company did not contribute to the plans during the three months ended March 31, 2018 and contributed $19 during the three months ended March 31, 2017. Total expected employer contributions during the year ending December 31, 2018 are $28.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Accumulated Other Comprehensive Loss	1 3 . Accumulated Other Comprehensive Loss The components of accumulated other comprehensive loss attributable to Fairmount Santrol Holdings Inc. at March 31, 2018 and December 31, 2017 were as follows: March 31, 2018 Gross Tax Effect Net Amount Foreign currency translation $ (10,233 ) $ 1,546 $ (8,687 ) Additional pension liability (3,193 ) 1,220 (1,973 ) Unrealized gain (loss) on interest rate hedges (6,214 ) 2,383 (3,831 ) $ (19,640 ) $ 5,149 $ (14,491 ) December 31, 2017 Gross Tax Effect Net Amount Foreign currency translation $ (10,249 ) $ 1,849 $ (8,400 ) Additional pension liability (3,253 ) 1,220 (2,033 ) Unrealized gain (loss) on interest rate hedges (7,283 ) 2,618 (4,665 ) $ (20,785 ) $ 5,687 $ (15,098 ) The following table presents the changes in accumulated other comprehensive loss by component for the three months ended March 31, 2018: Three Months Ended March 31, 2018 Unrealized Foreign Additional gain (loss) currency pension on interest translation liability rate hedges Total Beginning balance $ (8,400 ) $ (2,033 ) $ (4,665 ) $ (15,098 ) Other comprehensive income before reclassifications (287 ) - - (287 ) Amounts reclassified from accumulated other comprehensive loss - 60 834 894 Ending balance $ (8,687 ) $ (1,973 ) $ (3,831 ) $ (14,491 ) The following table presents the reclassifications out of accumulated other comprehensive loss during the three months ended March 31, 2018: Amount from accumulated Details about accumulated other other comprehensive Affected line item on comprehensive loss loss the statement of income (loss) Change in fair value of derivative swap agreements Interest rate hedging contracts $ 1,069 Interest expense Tax effect (235 ) Tax $ 834 Net of tax Amortization of pension obligations Actuarial losses $ 60 Cost of sales Total reclassifications for the period $ 894 Net of tax

Commitments and Contingent Liab

Commitments and Contingent Liabilities	3 Months Ended
	Mar. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities	1 4 . Commitments and Contingent Liabilities The Company has entered into numerous mineral rights agreements, in which payments under the agreements are expensed as incurred. Certain agreements require annual payments while other agreements require payments based upon annual tons mined and others a combination thereof. As of March 31, 2018, the Company is obligated for an additional $10,000 in future leasehold interest payments for the July 2017 Kermit, Texas transaction. This obligation is expected to be paid in the second quarter of 2018. Please refer to Note 4 for further detail. The Company has entered into agreements with third party terminal operators whereby certain minimum payments are due regardless of terminal utilization. The Company leases certain machinery, equipment (including railcars), buildings and office space under operating lease arrangements. Total rent expense associated with these leases was $13,127 and $13,714 for the three months ended March 31, 2018 and 2017, respectively. The Company is subject to a contingent consideration arrangement in the form of earnout payments, related to the purchase of SSP, which was accounted for as an acquisition of a group of assets. The earnout payments are based on a fixed percentage of the cumulative product margin, less certain adjustments, generated by sales of Propel SSP® and other products incorporating the SSP technology for five years commencing on October 1, 2015. The Company entered into an amendment to the SSP purchase agreement on December 17, 2015. This amendment (a) extends the period during which the threshold aggregate earnout payments equal or exceed $45,000 from the two-year period ending October 1, 2017 until the three-year period ending October 1, 2018; and (b) sets the threshold aggregate earnout payments during the two-year period ending October 1, 2017 to equal or exceed $15,000 and granted the Seller a security interest in 51% of the equity interests in the SSP technology to secure such $15,000. The amendment does not alter the final threshold earnout amount, which continues to be $195,000 (inclusive of the $45,000 payment, if any) by October 1, 2020. In the event the Company does not make the final threshold earnout payment, the Company would continue to retain a portion of the ownership interest in the technology, the right to a portion of future profits and would no longer be obligated for future earnout payments. It would also have the non-exclusive right to license the technology at a negotiated rate. Estimated earnout payments are accrued and capitalized as part of the cost of the acquired technology from the SSP acquisition at the time a payment is probable and reasonably estimable. Based upon current information, the Company has capitalized estimated earnout payments of $11,119, which includes total actual disbursements of $5,457 made through March 31, 2018. The seller elected not to exercise the claw-back of the technology as of October 1, 2017 as a result of the aggregate earnout payments being less than the $15,000 threshold at that date. As of March 31, 2018, the accrued balance of the earnout liability was $5,662, which represents the estimate of the total remaining aggregate earnout payments the Company expects to pay through October 1, 2020. Certain subsidiaries are defendants in lawsuits in which the alleged injuries are claimed to be silicosis-related and to have resulted, in whole or in part, from exposure to silica-containing products, allegedly including those sold by certain subsidiaries. In the majority of cases, there are numerous other defendants. In accordance with its insurance obligations, the defense of these actions has been tendered to and the cases are being defended by the subsidiaries’ insurance carriers. Management believes that the Company’s substantial level of existing and available insurance coverage combined with various open indemnities is more than sufficient to cover any exposure to silicosis-related expenses. An estimate of the possible loss, if any, cannot be made at this time. The Company has been named as a defendant in several lawsuits in which alleged stockholders claim the Company and its directors violated securities laws in connection with the current proposed merger transaction (defined in Note 19). The Company and its directors believe these allegations lack merit. An estimate of the possible loss, if any, cannot be made at this time.

Transactions with Related Parti

Transactions with Related Parties	3 Months Ended
	Mar. 31, 2018
Related Party Transactions [Abstract]
Transactions with Related Parties	1 5 . Transactions with Related Parties The Company pays American Securities LLC (“American Securities”), in accordance with its policy, for Board of Directors’ fees and Company-related expenses, including reimbursement for travel and lodging, market research, and other miscellaneous consulting fees and expenses. Fees and expenses paid to American Securities were $47 and $86 in the three months ended March 31, 2018 and 2017, respectively.

Segment Reporting

Segment Reporting	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Segment Reporting	1 6 . Segment Reporting The Company organizes its business into two reportable segments, Proppant Solutions and Industrial & Recreational Products. The reportable segments are consistent with how management views the markets served by the Company and the financial information reviewed by the chief operating decision maker in deciding how to allocate resources and assess performance. The chief operating decision maker primarily evaluates an operating segment’s performance based on segment gross profit, which does not include any selling, general, and administrative costs or corporate costs. Three Months Ended March 31, 2018 2017 Revenues Proppant Solutions $ 242,182 $ 140,993 Industrial & Recreational Products 31,156 31,590 Total revenues 273,338 172,583 Segment gross profit Proppant Solutions 76,114 25,461 Industrial & Recreational Products 11,146 12,919 Total segment gross profit 87,260 38,380 Operating expenses excluded from segment gross profit Selling, general, and administrative 27,353 22,470 Depreciation, depletion, and amortization 17,225 17,246 Other operating income (729 ) (1,060 ) Interest expense 13,783 12,537 Income (loss) before provision (benefit) for income taxes $ 29,628 $ (12,813 ) In the three months ended March 31, 2018, three customers exceeded 10% of revenues. These customers accounted for 29%, 11%, and 10% of revenues, respectively, in the three months ended March 31, 2018. In the three months ended March 31, 2017, three customers exceeded 10% of revenues. These customers accounted for 24%, 12%, and 11%, respectively, of revenues in the three months ended March 31, 2017. These are customers of the Company’s Proppant Solutions segment.

Goodwill and Intangibles

Goodwill and Intangibles	3 Months Ended
	Mar. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangibles	1 7 . Goodwill and Intangibles As of March 31, 2018, the balance of Goodwill was $15,301, which represents goodwill related to acquisitions in the Company’s Industrial & Recreational Products segment. As part of Company policy in its normal course of business, the Company performed a review of qualitative factors and concluded that, as of March 31, 2018, there were no events or changes in circumstances that would more likely than not result in an impairment of the carrying value of Goodwill. As of March 31, 2018, the balance of the FTSI supply agreement, net of accumulated amortization, was $29,659. At March 31, 2018, the balance of the SSP intangible asset, net of accumulated amortization, was $63,225. Please refer to Note 14 for additional information related to SSP.

Revenues from Contracts with Cu

Revenues from Contracts with Customers	3 Months Ended
	Mar. 31, 2018
Revenue From Contract With Customer [Abstract]
Revenues from Contracts with Customers	1 8 . Revenues from Contracts with Customers The Company’s revenues are primarily derived from contracts with customers with terms typically ranging from one to eight years in length. Variable Consideration The Company’s products may be sold with rebates, discounts, take-or-pay provisions, or other features which are accounted for as variable consideration. Rebates and discounts are not material and have not been separately disclosed. Contracts that contain take-or-pay provisions obligate customers to pay shortfall payments if the required volumes, as defined in the contracts, are not purchased. Shortfall payments are recognized as revenues when the likelihood of the customer purchasing the minimum volume becomes remote, subject to renegotiation of the contract and collectability. At March 31, 2018 and December 31, 2017, the Company had no accounts receivable related to shortfall payments. Disaggregated Revenues The following table presents the Company’s revenues disaggregated by reportable segment and by product line for the three months ended March 31, 2018 and 2017: Three Months Ended March 31, 2018 Proppant Solutions I&R Total Product lines Raw sand $ 191,176 $ 21,243 $ 212,419 Value-added products 51,006 9,913 60,919 Total revenues $ 242,182 $ 31,156 $ 273,338 Three Months Ended March 31, 2017 Proppant Solutions I&R Total Product lines Raw sand $ 102,834 $ 20,230 $ 123,064 Value-added products 38,159 11,360 49,519 Total revenues $ 140,993 $ 31,590 $ 172,583

Proposed Merger with Unimin Cor

Proposed Merger with Unimin Corporation	3 Months Ended
	Mar. 31, 2018
Business Combinations [Abstract]
Proposed Merger with Unimin Corporation	1 9 . Proposed Merger with Unimin Corporation On December 11, 2017, the Company entered into a merger agreement with Unimin Corporation (“Unimin”) and certain other parties with respect to the proposed combination of the businesses of Unimin and Fairmount Santrol. The merger agreement provides that, upon the satisfaction or waiver of the conditions contained in the agreement, a direct wholly owned subsidiary of Unimin will be merged with and into Fairmount Santrol, with Fairmount Santrol surviving such merger and becoming a direct wholly owned subsidiary of Unimin (the “Merger”). In accordance with the terms of the Merger agreement (“Merger Agreement”), Fairmount Santrol stockholders in the aggregate (including holders of certain Fairmount Santrol equity awards) will receive $170,000 in cash and approximately 35% of the common stock of Unimin, with SCR-Sibelco NV (“Sibelco”), the existing parent company of Unimin, owning the remaining 65%. The Merger is subject to, among other things, approval by Fairmount Santrol’s stockholders, listing of Unimin’s common stock on the New York Stock Exchange (“NYSE”), and certain regulatory approvals. The Company will hold a special meeting of its stockholders on May 25, 2018 (the “Special Meeting”) to vote to approve the Merger, among other items. Upon completion of the Merger, the Company would delist and no longer trade on the NYSE. The transaction is expected to close in mid-2018, subject to satisfaction of the closing conditions. Were the transaction to close, Internal Revenue Code Sections 382 and 383 could limit post-merger annual utilization of U.S. federal net operating losses and tax credits. The Merger Agreement contains certain conditional termination rights and, if exercised, the Company may be required to pay Unimin a termination fee of $52,000. The Company has incurred $11,645 of expenses associated with the Merger, which are recorded in selling, general and administrative expenses in the Condensed Consolidated Statements of Income (Loss). In the three months ended March 31, 2018, the Company has incurred $3,334 of such expenses, with the remaining balance primarily recorded in the fourth quarter of 2017. For further information on the Merger, refer to the Merger Agreement, a copy of which was filed as Exhibit 2.1 to our Current Report on Form 8-K filed with the SEC on December 12, 2017.

Significant Accounting Polici27

Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The unaudited condensed consolidated financial statements of Fairmount Santrol Holdings Inc. and its consolidated subsidiaries (collectively, the “Company”) have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, the unaudited condensed consolidated financial statements reflect all adjustments (which are of a normal, recurring nature) and disclosures necessary for a fair statement of the financial position, results of operations, comprehensive income, and cash flows of the reported interim periods. The Condensed Consolidated Balance Sheets as of December 31, 2017 was derived from audited financial statements, but does not include all disclosures required by GAAP. Certain reclassifications of prior year amounts have been made to conform to current year presentation. Interim results are not necessarily indicative of the results to be expected for the full year or any other interim period. These unaudited condensed consolidated financial statements should be read in conjunction with the Company’s consolidated financial statements as filed in the 2017 Annual Report on Form 10-K and notes thereto and information included elsewhere in this Quarterly Report on Form 10-Q.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates.
Revisions of Previously-Issued Financial Statements	Revisions of Previously-Issued Financial Statements The Company has revised previously-reported results to properly report stripping costs that were previously capitalized when incurred and amortized in subsequent periods. Such costs incurred during the production phase of a mine are variable production costs that should be included in the costs of the inventory produced during the period the stripping costs are incurred. The Company also revised the asset impairment charge for the quarter ended June 30, 2016 to correct its estimated fair value for an impaired mine property included in the determination of the impairment charge. Additionally, the Company has included in the revised statements of cash flows a previously-omitted disclosure to show increase or decrease in accounts payable for additions to property, plant, and equipment. The Company assessed the materiality of these misstatements on prior periods’ financial statements and concluded that these misstatements were not material, individually or in aggregate, to any previously-issued financial statements. Refer to Note 2 for additional information.
Revenues	Revenues The Company derives its revenues by mining, manufacturing, and processing minerals that its customers purchase for various uses. Revenues are measured by the amount of consideration the Company expects to receive in exchange for transferring its product. The consideration the Company expects to receive is based on volumes and price of product as defined in the underlying contract. Depending on the contract, this may include the cost of transportation and may be net of discounts and rebates. In some instances, revenues also include a separate charge for transportation services the Company provides or arranges for customers. On January 1, 2018, the Company adopted Revenue from Contracts with Customers
Accounts Receivable – Contract Balances	Accounts Receivable – Contract Balances Accounts receivable as presented in the consolidated balance sheets are related to the Company’s contracts and are recorded when the right to consideration becomes unconditional at the amount management expects to collect. Accounts receivable do not bear interest if paid when contractually due, and payments are generally due within thirty to forty-five days of invoicing. Accounts receivable, net of allowance for doubtful accounts, are $179,234 and $156,916 as of March 31, 2018 and December 31, 2017, respectively. The Company typically does not record contract assets, as the transfer of control of its products results in an unconditional right to receive consideration.
Deferred Revenues – Contract Balances	Deferred Revenues – Contract Balances The Company enters into certain contracts with customers that include provisions requiring receipt of payment at the inception of the contract. Deferred revenue is recorded when payment is received or due in advance of the performance obligation. Changes in deferred revenue were as follows: Three Months Ended March 31, 2018 Beginning balance $ 8,963 Deferral of revenue 5,000 Recognition of unearned revenue (678 ) Ending balance $ 13,285 At March 31, 2018 and December 31, 2017, respectively, deferred revenue balances of $9,346 and $5,660 were recorded as current liabilities. At March 31, 2018 and December 31, 2017, respectively, deferred revenue balances of $3,939 and $3,303 were recorded in other long-term liabilities.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Recently Adopted Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09 – Revenue from Contracts with Customers (Topic 606) Topic 605 – Revenue Recognition On January 1, 2018, the Company adopted the ASU for all contracts which were not completed as of January 1, 2018 using the modified retrospective transition method. The adoption did not require a cumulative adjustment to opening retained earnings and did not have a material impact on revenues for the quarter ended March 31, 2018. See Note 18 for further details. In March 2017, the FASB issued ASU No. 2017-07 – Compensation – Retirement Benefits (Topic 715) – Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost Recently Issued Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02 – Leases (Topic 842) In August 2017, the FASB issued ASU No. 2017-12 – Derivatives and Hedging (Topic 815) – Targeted Improvements to Accounting for Hedging Activities In February 2018, the FASB issued ASU No. 2018-02 – Income Statement – Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income In March 2018, the FASB issued ASU no. 2018-05 – Income Taxes (Topic 740): Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118.

Significant Accounting Polici28

Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Summary of Changes in Deferred Revenue	Changes in deferred revenue were as follows: Three Months Ended March 31, 2018 Beginning balance $ 8,963 Deferral of revenue 5,000 Recognition of unearned revenue (678 ) Ending balance $ 13,285

Revisions of Previously-Repor29

Revisions of Previously-Reported Results (Tables)	3 Months Ended
	Mar. 31, 2018
Accounting Changes And Error Corrections [Abstract]
Impact of Revisions on Consolidated Financial Statements	The following tables show the impact of these revisions on all of the impacted line items from the Company’s (i) unaudited condensed consolidated financial statements for the three months ended March 31, 2017 and (ii) consolidated financial statements as of December 31, 2017 and 2016, and for the years ended December 31, 2017, 2016, and 2015: Consolidated Statement of Loss Three Months Ended March 31, 2017 As Reported Adjustments As Corrected (in thousands, except per share amounts) Revenues $ 172,583 $ - $ 172,583 Cost of goods sold (excluding depreciation, depletion, and amortization shown separately) 131,752 2,451 134,203 Operating expenses Selling, general and administrative expenses 22,470 - 22,470 Depreciation, depletion and amortization expense 19,442 (2,196 ) 17,246 Other operating (income) expense (1,060 ) - (1,060 ) Income (loss) from operations (21 ) (255 ) (276 ) Interest expense 12,537 - 12,537 Income (loss) before benefit from income taxes (12,558 ) (255 ) (12,813 ) Benefit from income taxes (1,148 ) (12 ) (1,160 ) Net income (loss) (11,410 ) (243 ) (11,653 ) Less: Net income attributable to the non-controlling interest 178 - 178 Net income (loss) attributable to Fairmount Santrol Holdings Inc. $ (11,588 ) $ (243 ) $ (11,831 ) Loss per share Basic $ (0.05 ) $ - $ (0.05 ) Diluted $ (0.05 ) $ - $ (0.05 ) Weighted average number of shares outstanding Basic 223,739 ― 223,739 Diluted 223,739 ― 223,739 Consolidated Statement of Income Year Ended December 31, 2017 As Reported Adjustments As Corrected (in thousands, except per share amounts) Revenues $ 959,795 $ - $ 959,795 Cost of goods sold (excluding depreciation, depletion, and amortization shown separately) 659,758 11,443 671,201 Operating expenses Selling, general and administrative expenses 113,240 - 113,240 Depreciation, depletion and amortization expense 79,144 (9,734 ) 69,410 Other operating income (1,072 ) - (1,072 ) Income from operations 108,725 (1,709 ) 107,016 Interest expense 56,408 - 56,408 Loss on debt extinguishment, net 2,898 - 2,898 Income before benefit from income taxes 49,419 (1,709 ) 47,710 Benefit from income taxes (4,666 ) (1,049 ) (5,715 ) Net income 54,085 (660 ) 53,425 Less: Net income attributable to the non-controlling interest 297 - 297 Net income attributable to Fairmount Santrol Holdings Inc. $ 53,788 $ (660 ) $ 53,128 Earnings per share Basic $ 0.24 $ - $ 0.24 Diluted $ 0.23 $ - $ 0.23 Weighted average number of shares outstanding Basic 223,993 ― 223,993 Diluted 229,084 ― 229,084 Consolidated Statement of Loss Year Ended December 31, 2016 As Reported Adjustments As Corrected (in thousands, except per share amounts) Revenues $ 535,013 $ - $ 535,013 Cost of goods sold (excluding depreciation, depletion, and amortization shown separately) 459,714 9,803 469,517 Operating expenses Selling, general and administrative expenses 79,140 - 79,140 Depreciation, depletion and amortization expense 72,276 (8,962 ) 63,314 Goodwill and other asset impairments 93,148 (3,297 ) 89,851 Restructuring charges 1,155 - 1,155 Other operating expense 8,899 - 8,899 Loss from operations (179,319 ) 2,456 (176,863 ) Interest expense 65,367 - 65,367 Gain on repurchase of debt, net (5,110 ) - (5,110 ) Other non-operating income (10 ) - (10 ) Loss before benefit from income taxes (239,566 ) 2,456 (237,110 ) Benefit from income taxes (99,441 ) 10,811 (88,630 ) Net loss (140,125 ) (8,355 ) (148,480 ) Less: Net income attributable to the non-controlling interest 67 - 67 Net loss attributable to Fairmount Santrol Holdings Inc. $ (140,192 ) $ (8,355 ) $ (148,547 ) Loss per share Basic $ (0.78 ) $ (0.05 ) $ (0.83 ) Diluted $ (0.78 ) $ (0.05 ) $ (0.83 ) Weighted average number of shares outstanding Basic 179,429 ― 179,429 Diluted 179,429 ― 179,429 Consolidated Statement of Loss Year Ended December 31, 2015 As Reported Adjustments As Corrected (in thousands, except per share amounts) Revenues $ 828,709 $ - $ 828,709 Cost of goods sold (excluding depreciation, depletion, and amortization shown separately) 608,845 7,175 616,020 Operating expenses Selling, general and administrative expenses 85,191 - 85,191 Depreciation, depletion and amortization expense 66,754 (6,348 ) 60,406 Goodwill and other asset impairments 87,476 - 87,476 Restructuring charges 9,221 - 9,221 Other operating expense 1,357 (378 ) 979 Loss from operations (30,135 ) (449 ) (30,584 ) Interest expense 62,242 - 62,242 Other non-operating expense 1,492 - 1,492 Loss before benefit from income taxes (93,869 ) (449 ) (94,318 ) Benefit from income taxes (1,939 ) (164 ) (2,103 ) Net loss (91,930 ) (285 ) (92,215 ) Less: Net income attributable to the non-controlling interest 205 - 205 Net loss attributable to Fairmount Santrol Holdings Inc. $ (92,135 ) $ (285 ) $ (92,420 ) Loss per share Basic $ (0.57 ) $ - $ (0.57 ) Diluted $ (0.57 ) $ - $ (0.57 ) Weighted average number of shares outstanding Basic 161,297 ― 161,297 Diluted 161,297 ― 161,297 Consolidated Statement of Comprehensive Loss Three Months Ended March 31, 2017 As Reported Adjustments As Corrected (in thousands) Net loss $ (11,410 ) $ (243 ) $ (11,653 ) Other comprehensive income, before tax Foreign currency translation (39 ) - (39 ) Pension obligations 61 - 61 Change in fair value of derivative agreements 1,613 - 1,613 Total other comprehensive income, before tax 1,635 - 1,635 Provision for income taxes related to items of other comprehensive income 1,316 - 1,316 Comprehensive loss, net of tax (11,091 ) (243 ) (11,334 ) Comprehensive income attributable to the non-controlling interest 178 - 178 Comprehensive loss attributable to Fairmount Santrol Holdings Inc. $ (11,269 ) $ (243 ) $ (11,512 ) Consolidated Statement of Comprehensive Income Year Ended December 31, 2017 As Reported Adjustments As Corrected (in thousands) Net income $ 54,085 $ (660 ) $ 53,425 Other comprehensive income, before tax Foreign currency translation 555 - 555 Pension obligations 336 - 336 Change in fair value of derivative agreements 5,863 - 5,863 Total other comprehensive income, before tax 6,754 - 6,754 Provision for income taxes related to items of other comprehensive income 2,850 - 2,850 Comprehensive income, net of tax 57,989 (660 ) 57,329 Comprehensive income attributable to the non-controlling interest 297 - 297 Comprehensive income attributable to Fairmount Santrol Holdings Inc. $ 57,692 $ (660 ) $ 57,032 Consolidated Statement of Comprehensive Loss Year Ended December 31, 2016 As Reported Adjustments As Corrected (in thousands) Net loss $ (140,125 ) $ (8,355 ) $ (148,480 ) Other comprehensive loss, before tax Foreign currency translation (774 ) - (774 ) Pension obligations 425 - 425 Change in fair value of derivative agreements (3,018 ) - (3,018 ) Total other comprehensive loss, before tax (3,367 ) - (3,367 ) Benefit from income taxes related to items of other comprehensive loss (2,058 ) - (2,058 ) Comprehensive loss, net of tax (141,434 ) (8,355 ) (149,789 ) Comprehensive income attributable to the non-controlling interest 67 - 67 Comprehensive loss attributable to Fairmount Santrol Holdings Inc. $ (141,501 ) $ (8,355 ) $ (149,856 ) Consolidated Statement of Comprehensive Loss Year Ended December 31, 2015 As Reported Adjustments As Corrected (in thousands) Net loss $ (91,930 ) $ (285 ) $ (92,215 ) Other comprehensive loss, before tax Foreign currency translation (5,051 ) - (5,051 ) Pension obligations 222 - 222 Change in fair value of derivative agreements (1,836 ) - (1,836 ) Total other comprehensive loss, before tax (6,665 ) - (6,665 ) Benefit from income taxes related to items of other comprehensive loss (1,780 ) - (1,780 ) Comprehensive loss, net of tax (96,815 ) (285 ) (97,100 ) Comprehensive income attributable to the non-controlling interest 205 - 205 Comprehensive loss attributable to Fairmount Santrol Holdings Inc. $ (97,020 ) $ (285 ) $ (97,305 ) Consolidated Balance Sheet December 31, 2017 As Reported Adjustments As Corrected (in thousands) Assets Current assets Cash and cash equivalents $ 127,967 $ - $ 127,967 Accounts receivable, net of allowance for doubtful accounts of $2,003 at December 31, 2017 156,916 - 156,916 Inventories, net 70,528 - 70,528 Prepaid expenses and other assets 6,841 - 6,841 Refundable income taxes 924 - 924 Total current assets 363,176 - 363,176 Property, plant and equipment, net 785,513 (29,225 ) 756,288 Deferred income taxes 350 - 350 Goodwill 15,301 - 15,301 Intangibles, net 93,268 - 93,268 Other assets 7,711 - 7,711 Total assets $ 1,265,319 $ (29,225 ) $ 1,236,094 Liabilities and Equity Current liabilities Current portion of long-term debt $ 19,189 $ - $ 19,189 Accounts payable 70,633 - 70,633 Accrued expenses 74,007 - 74,007 Deferred revenue 5,660 - 5,660 Total current liabilities 169,489 - 169,489 Long-term debt 729,741 - 729,741 Deferred income taxes 3,606 (1,177 ) 2,429 Other long-term liabilities 42,189 - 42,189 Total liabilities 945,025 (1,177 ) 943,848 Commitments and contingent liabilities Equity Preferred stock: $0.01 par value, 100,000 authorized shares Shares outstanding: 0 at December 31, 2017 - - - Common stock: $0.01 par value, 1,850,000 authorized shares Shares issued: 242,366 at December 31, 2017 Shares outstanding: 224,291 at December 31, 2017 2,423 - 2,423 Additional paid-in capital 299,912 - 299,912 Retained earnings 318,207 (28,048 ) 290,159 Accumulated other comprehensive loss (15,098 ) - (15,098 ) Total equity attributable to Fairmount Santrol Holdings Inc. before treasury stock 605,444 (28,048 ) 577,396 Less: Treasury stock at cost Shares in treasury: 18,075 at December 31, 2017 (285,520 ) - (285,520 ) Total equity attributable to Fairmount Santrol Holdings Inc. 319,924 (28,048 ) 291,876 Non-controlling interest 370 - 370 Total equity 320,294 (28,048 ) 292,246 Total liabilities and equity $ 1,265,319 $ (29,225 ) $ 1,236,094 Consolidated Balance Sheet December 31, 2016 As Reported Adjustments As Corrected (in thousands) Assets Current assets Cash and cash equivalents $ 194,069 $ - $ 194,069 Accounts receivable, net of allowance for doubtful accounts of $3,055 at December 31, 2016 78,942 - 78,942 Inventories, net 52,650 - 52,650 Prepaid expenses and other assets 7,065 - 7,065 Refundable income taxes 21,077 - 21,077 Total current assets 353,803 - 353,803 Property, plant and equipment, net 727,735 (27,514 ) 700,221 Deferred income taxes 1,244 - 1,244 Goodwill 15,301 - 15,301 Intangibles, net 95,341 - 95,341 Other assets 9,486 - 9,486 Total assets $ 1,202,910 $ (27,514 ) $ 1,175,396 Liabilities and Equity Current liabilities Current portion of long-term debt $ 10,707 $ - $ 10,707 Accounts payable 37,263 - 37,263 Accrued expenses 26,110 - 26,110 Deferred revenue 75 - 75 Total current liabilities 74,155 - 74,155 Long-term debt 832,306 - 832,306 Deferred income taxes 7,057 (128 ) 6,929 Other long-term liabilities 38,272 - 38,272 Total liabilities 951,790 (128 ) 951,662 Commitments and contingent liabilities Equity Preferred stock: $0.01 par value, 100,000 authorized shares Shares outstanding: 0 at December 31, 2016 - - - Common stock: $0.01 par value, 1,850,000 authorized shares Shares issued: 242,267 at December 31, 2016 Shares outstanding: 223,601 at December 31, 2016 2,422 - 2,422 Additional paid-in capital 297,649 - 297,649 Retained earnings 264,852 (27,386 ) 237,466 Accumulated other comprehensive loss (19,002 ) - (19,002 ) Total equity attributable to Fairmount Santrol Holdings Inc. before treasury stock 545,921 (27,386 ) 518,535 Less: Treasury stock at cost Shares in treasury: 18,666 at December 31, 2016 (294,874 ) - (294,874 ) Total equity attributable to Fairmount Santrol Holdings Inc. 251,047 (27,386 ) 223,661 Non-controlling interest 73 - 73 Total equity 251,120 (27,386 ) 223,734 Total liabilities and equity $ 1,202,910 $ (27,514 ) $ 1,175,396 Consolidated Statement of Cash Flows Three Months Ended March 31, 2017 As Reported Adjustments As Corrected (in thousands) Net loss $ (11,410 ) $ (243 ) $ (11,653 ) Adjustments to reconcile net loss to net cash provided by operating activities: Depreciation and depletion 17,530 (2,196 ) 15,334 Amortization 3,130 - 3,130 Reserve for doubtful accounts (447 ) - (447 ) Gain on disposal of fixed assets (714 ) - (714 ) Deferred income taxes and taxes payable 119 (12 ) 107 Stock compensation expense 2,416 - 2,416 Change in operating assets and liabilities: Accounts receivable (15,956 ) - (15,956 ) Inventories (9,038 ) - (9,038 ) Prepaid expenses and other assets (1,078 ) 1,945 867 Refundable income taxes 1,945 (1,945 ) - Accounts payable 12,981 - 12,981 Accrued expenses and deferred revenue 26,489 (26,489 ) - Accrued expenses - 9,744 9,744 Deferred revenue - 16,969 16,969 Net cash provided by operating activities 25,967 (2,227 ) 23,740 Cash flows from investing activities Proceeds from sale of fixed assets 957 - 957 Capital expenditures and stripping costs (7,025 ) 2,451 (4,574 ) Other investing activities (758 ) 758 - Net cash used in investing activities (6,826 ) 3,209 (3,617 ) Cash flows from financing activities Payments on term loans (2,170 ) - (2,170 ) Payments on capital leases and other long-term debt (817 ) - (817 ) Proceeds from share-based awards exercised or distributed 486 - 486 Tax payments for withholdings on share-based awards exercised or distributed - (982 ) (982 ) Transactions with non-controlling interest (1 ) - (1 ) Net cash used in financing activities (2,502 ) (982 ) (3,484 ) Foreign currency adjustment (44 ) - (44 ) Increase in cash and cash equivalents 16,595 - 16,595 Cash and cash equivalents: Beginning of period 194,069 - 194,069 End of period $ 210,664 $ - $ 210,664 Supplemental disclosure of cash flow information: Interest paid, net of capitalized interest $ 11,717 Income taxes refunded (1,601 ) Non-cash investing activities: Equipment purchased under capital leases $ 4,175 Decrease in accounts payable for additions to property, plant, and equipment (1,301 ) Consolidated Statement of Cash Flows Year Ended December 31, 2017 As Reported Adjustments As Corrected (in thousands) Net income $ 54,085 $ (660 ) $ 53,425 Adjustments to reconcile net income to net cash provided by operating activities: Depreciation and depletion 71,397 (9,734 ) 61,663 Amortization 12,784 - 12,784 Reserve for doubtful accounts (387 ) - (387 ) Write-off of deferred financing costs 389 - 389 Loss on debt extinguishment, gross 2,898 - 2,898 Inventory write-downs and reserves 1,266 - 1,266 Loss on disposal of fixed assets 846 - 846 Unrealized loss on interest rate swaps 14 - 14 Deferred income taxes and taxes payable (5,634 ) (1,049 ) (6,683 ) Stock compensation expense 10,071 - 10,071 Change in operating assets and liabilities: Accounts receivable (77,587 ) - (77,587 ) Inventories (19,144 ) - (19,144 ) Prepaid expenses and other assets (2,398 ) - (2,398 ) Refundable income taxes 20,154 - 20,154 Accounts payable 18,575 - 18,575 Accrued expenses 51,874 - 51,874 Deferred revenue 5,585 - 5,585 Net cash provided by operating activities 144,788 (11,443 ) 133,345 Cash flows from investing activities Proceeds from sale of fixed assets 4,939 - 4,939 Capital expenditures and stripping costs (69,573 ) 11,443 (58,130 ) Leasehold interest payments for sand reserves (30,000 ) - (30,000 ) Earnout payments (4,170 ) - (4,170 ) Net cash used in investing activities (98,804 ) 11,443 (87,361 ) Cash flows from financing activities Proceeds from borrowings on term loan 689,500 - 689,500 Payments on term loans (6,469 ) - (6,469 ) Prepayments on term loans (832,655 ) - (832,655 ) Fees for debt restructure and repurchase of term loans (2,790 ) - (2,790 ) Payments on capital leases and other long-term debt (4,752 ) - (4,752 ) Proceeds from borrowing on revolving credit facility 50,000 - 50,000 Payments on revolving credit facility (5,000 ) - (5,000 ) Proceeds from option exercises 845 - 845 Tax payments for withholdings on share-based awards exercised or distributed (1,321 ) - (1,321 ) Net cash used in financing activities (112,642 ) - (112,642 ) Foreign currency adjustment 556 - 556 Decrease in cash and cash equivalents (66,102 ) - (66,102 ) Cash and cash equivalents: Beginning of period 194,069 - 194,069 End of period $ 127,967 $ - $ 127,967 Supplemental disclosure of cash flow information: Interest paid, net of capitalized interest $ 59,498 Income taxes refunded (19,278 ) Non-cash investing activities: Equipment purchased under capital leases $ 10,988 Decrease in accounts payable for additions to property, plant, and equipment (14,796 ) Consolidated Statement of Cash Flows Year Ended December 31, 2016 As Reported Adjustments As Corrected (in thousands) Net loss $ (140,125 ) $ (8,355 ) $ (148,480 ) Adjustments to reconcile net loss to net cash provided by (used in) operating activities: Depreciation and depletion 67,614 (8,962 ) 58,652 Amortization 11,641 - 11,641 Reserve for doubtful accounts 1,851 - 1,851 Write-off of deferred financing costs 2,618 - 2,618 Gain on repurchase of debt, gross (8,178 ) - (8,178 ) Goodwill and other asset impairments 93,148 (3,297 ) 89,851 Inventory write-downs and reserves 10,302 - 10,302 Loss on disposal of fixed assets 420 - 420 Deferred income taxes and taxes payable (82,732 ) 10,811 (71,921 ) Stock compensation expense 8,870 - 8,870 Change in operating assets and liabilities: Accounts receivable (4,385 ) - (4,385 ) Inventories 7,543 - 7,543 Prepaid expenses and other assets 11,496 - 11,496 Refundable income taxes 5,428 - 5,428 Accounts payable 4,196 - 4,196 Accrued expenses 11,718 - 11,718 Deferred revenue 75 - 75 Net cash provided by (used in) operating activities 1,500 (9,803 ) (8,303 ) Cash flows from investing activities Proceeds from sale of fixed assets 5,670 - 5,670 Capital expenditures and stripping costs (30,597 ) 9,803 (20,794 ) Earnout payments (1,287 ) - (1,287 ) Net cash used in investing activities (26,214 ) 9,803 (16,411 ) Cash flows from financing activities Payments on term loans (10,840 ) - (10,840 ) Prepayments on term loans (155,926 ) - (155,926 ) Repurchase of term loans (216,000 ) - (216,000 ) Fees for debt restructure and repurchase of term loans (450 ) - (450 ) Payments on capital leases and other long-term debt (5,947 ) - (5,947 ) Proceeds from option exercises 6,438 - 6,438 Proceeds from primary stock offering 439,556 - 439,556 Tax payments for withholdings on share-based awards exercised or distributed (8,092 ) - (8,092 ) Tax effect of share-based awards exercised, forfeited, or expired (1,100 ) - (1,100 ) Transactions with non-controlling interest (842 ) - (842 ) Net cash provided by financing activities 46,797 - 46,797 Change in cash and cash equivalents related to assets classified as held-for-sale 1,376 - 1,376 Foreign currency adjustment (876 ) - (876 ) Increase in cash and cash equivalents 22,583 - 22,583 Cash and cash equivalents: Beginning of period 171,486 - 171,486 End of period $ 194,069 $ - $ 194,069 Supplemental disclosure of cash flow information: Interest paid, net of capitalized interest $ 60,833 Income taxes refunded (21,311 ) Non-cash investing activities: Equipment purchased under capital leases $ - Increase in accounts payable for additions to property, plant, and equipment 8,100 Consolidated Statement of Cash Flows Year Ended December 31, 2015 As Reported Adjustments As Corrected (in thousands) Net loss $ (91,930 ) $ (285 ) $ (92,215 ) Adjustments to reconcile net loss to net cash provided by operating activities: Depreciation and depletion 62,218 (6,348 ) 55,870 Amortization 11,416 - 11,416 Reserve for doubtful accounts 1,968 - 1,968 Write-off of deferred financing costs 864 - 864 Goodwill and other asset impairments 76,038 - 76,038 Non-cash restructuring charges 1,162 - 1,162 Inventory write-downs and reserves 1,591 - 1,591 Loss on disposal of fixed assets 8,712 - 8,712 Unrealized loss on interest rate swaps 49 - 49 Deferred income taxes and taxes payable 20,983 (164 ) 20,819 Stock compensation expense 4,525 - 4,525 Change in operating assets and liabilities: Accounts receivable 127,718 - 127,718 Inventories 59,527 - 59,527 Prepaid expenses and other assets 23,234 - 23,234 Refundable income taxes (26,506 ) - (26,506 ) Accounts payable (38,698 ) - (38,698 ) Accrued expenses (6,051 ) - (6,051 ) Net cash provided by operating activities 236,820 (6,797 ) 230,023 Cash flows from investing activities Capital expenditures and stripping costs (113,750 ) 6,797 (106,953 ) Other investing activities (250 ) - (250 ) Net cash used in investing activities (114,000 ) 6,797 (107,203 ) Cash flows from financing activities Payments on term loans (13,532 ) - (13,532 ) Payments on capital leases and other long-term debt (6,975 ) - (6,975 ) Proceeds from option exercises 1,767 - 1,767 Tax payments for withholdings on share-based awards exercised or distributed (826 ) - (826 ) Tax effect of share-based awards exercised, forfeited, or expired (1,472 ) - (1,472 ) Transactions with non-controlling interest (301 ) - (301 ) Other financing activities (4,578 ) - (4,578 ) Net cash used in financing activities (25,917 ) - (25,917 ) Change in cash and cash equivalents related to assets classified as held-for-sale (1,376 ) - (1,376 ) Foreign currency adjustment (964 ) - (964 ) Increase in cash and cash equivalents 94,563 - 94,563 Cash and cash equivalents: Beginning of period 76,923 - 76,923 End of period $ 171,486 $ - $ 171,486 Supplemental disclosure of cash flow information: Interest paid, net of capitalized interest $ 61,395 Income taxes refunded (19,898 ) Non-cash investing activities: Equipment purchased under capital leases $ 4,552 Increase in accounts payable for additions to property, plant, and equipment 652

Inventories, net (Tables)

Inventories, net (Tables)	3 Months Ended
	Mar. 31, 2018
Inventory Disclosure [Abstract]
Schedule of Inventories	At March 31, 2018 and December 31, 2017, inventories consisted of the following: March 31, 2018 December 31, 2017 Raw materials $ 8,368 $ 7,412 Work-in-process 10,303 14,819 Finished goods 46,848 48,931 65,519 71,162 Less: LIFO reserve (624 ) (634 ) Inventories, net $ 64,895 $ 70,528

Property, Plant, and Equipmen31

Property, Plant, and Equipment, net (Tables)	3 Months Ended
	Mar. 31, 2018
Property Plant And Equipment [Abstract]
Schedule of Property, Plant, and Equipment	At March 31, 2018 and December 31, 2017, property, plant, and equipment consisted of the following: March 31, 2018 December 31, 2017 Land and improvements $ 83,491 $ 85,012 Mineral reserves and mine development 228,356 222,271 Machinery and equipment 601,745 590,584 Buildings and improvements 186,631 186,466 Furniture, fixtures, and other 3,492 3,478 Construction in progress 81,125 54,661 1,184,840 1,142,472 Accumulated depletion and depreciation (401,411 ) (386,184 ) Property, plant, and equipment, net $ 783,429 $ 756,288

Long-Term Debt (Tables)

Long-Term Debt (Tables)	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Schedule of Long-Term Debt	At March 31, 2018 and December 31, 2017, long-term debt consisted of the following: March 31, 2018 December 31, 2017 Term Loan B $ 685,184 $ 688,990 Industrial Revenue Bond 10,000 10,000 ABL Revolver, Revolving Credit Facility, and other 35,056 45,073 Capital leases, net 8,738 9,884 Deferred financing costs, net (4,738 ) (5,017 ) 734,240 748,930 Less: current portion (18,924 ) (19,189 ) Long-term debt including leases $ 715,316 $ 729,741

Accrued Expenses (Tables)

Accrued Expenses (Tables)	3 Months Ended
	Mar. 31, 2018
Payables And Accruals [Abstract]
Summary of Accrued Expenses	At March 31, 2018 and December 31, 2017, accrued expenses consisted of the following: March 31, 2018 December 31, 2017 Accrued payroll and fringe benefits $ 8,526 $ 11,233 Accrued bonus 3,543 37,166 Accrued income taxes 386 504 Accrued real estate taxes 4,617 5,098 Accrued leasehold interest payments 10,000 10,000 Other accrued expenses 14,588 10,006 Accrued expenses $ 41,660 $ 74,007

Earnings (Loss) per Share (Tabl

Earnings (Loss) per Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Computation of Basic and Diluted Earnings (Loss) per Share	The table below shows the computation of basic and diluted earnings (loss) per share for the three months ended March 31, 2018 and 2017, respectively: Three Months Ended March 31, 2018 2017 Numerator: Net income (loss) attributable to Fairmount Santrol Holdings Inc. $ 28,753 $ (11,831 ) Denominator: Basic weighted average shares outstanding 224,484 223,739 Dilutive effect of employee stock options, RSUs, and PRSUs 4,456 - Diluted weighted average shares outstanding 228,940 223,739 Earnings (loss) per common share – basic $ 0.13 $ (0.05 ) Earnings (loss) per common share – diluted $ 0.13 $ (0.05 )

Derivative Instruments (Tables)

Derivative Instruments (Tables)	3 Months Ended
	Mar. 31, 2018
Derivatives, Fair Value [Line Items]
Fair Values of Derivative Instrument and Respective Classification in Condensed Consolidated Balance Sheets	The following table summarizes the fair values and the respective classification in the Condensed Consolidated Balance Sheets as of March 31, 2018 and December 31, 2017: Assets (Liabilities) Interest Rate Swap Agreements Balance Sheet Classification March 31, 2018 December 31, 2017 Non-qualifying cash flow hedge Other long-term liabilities $ (1,394 ) $ (3,208 ) $ (1,394 ) $ (3,208 )
Designated as Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Schedule of Interest Expense Recognized on Derivative	The Company recognized in interest expense the following in the three months ended March 31, 2018 and 2017, respectively, in order to represent the ineffective portion of interest rate swap agreements designated as hedges and interest rate swap agreements no longer qualifying for hedge accounting treatment: Derivatives Designated as Location of (Gain) Loss ASC 815-20 Cash Flow Recognized in Income on Three Months Ended March 31, Hedging Relationships Derivative (Ineffective Portion) 2018 2017 Interest rate swap agreements Interest expense $ - $ (77 ) $ - $ (77 )
Derivatives Not Designated as Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Schedule of Interest Expense Recognized on Derivative	Derivatives Not Designated as ASC 815-20 Cash Flow Location of (Gain) Loss Three Months Ended March 31, Hedging Relationships Recognized in Income on Derivative 2018 2017 Interest rate swap agreements Interest expense $ (99 ) $ - $ (99 ) $ -

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Schedule of Fair Value for Long-term Debt	The following table presents the fair value as of March 31, 2018 and December 31, 2017, respectively, for the Company’s long-term debt: Quoted Other in Active Observable Unobservable Markets Inputs Inputs Long-Term Debt Fair Value Measurements (Level 1) (Level 2) (Level 3) Total March 31, 2018 Term Loan B $ - $ 704,320 $ - $ 704,320 $ - $ 704,320 $ - $ 704,320 December 31, 2017 Term Loan B $ - $ 708,750 $ - $ 708,750 $ - $ 708,750 $ - $ 708,750
Financial Instruments Carried at Fair Value	The following table presents the amounts carried at fair value as of March 31, 2018 and December 31, 2017 for the Company’s other financial instruments. Fair value of interest rate swap agreements is based on the present value of the expected future cash flows, considering the risks involved, and using discount rates appropriate for the maturity date. These are determined using Level 2 inputs. Quoted Other in Active Observable Unobservable Markets Inputs Inputs Recurring Fair Value Measurements (Level 1) (Level 2) (Level 3) Total March 31, 2018 Interest rate swap agreements $ - $ (1,394 ) $ - $ (1,394 ) $ - $ (1,394 ) $ - $ (1,394 ) December 31, 2017 Interest rate swap agreements $ - $ (3,208 ) $ - $ (3,208 ) $ - $ (3,208 ) $ - $ (3,208 )

Common Stock and Stock-Based 37

Common Stock and Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Share Based Compensation Activity of Option and Non-option Instruments	Weighted Weighted Performance Weighted Average Exercise Restricted Average Price at Restricted Average Price at Options Price, Options Stock Units RSU Issue Date Stock Units PRSU Issue Date Outstanding at December 31, 2017 13,393 $ 6.63 1,517 $ 6.63 584 $ 4.10 Granted - - 1,581 4.56 - - Exercised (355 ) 2.58 (280 ) 4.65 - - Forfeited (9 ) 10.70 (6 ) 10.03 - - Expired (4 ) 16.00 - - - - Outstanding at March 31, 2018 13,025 $ 6.73 2,812 $ 5.67 584 $ 4.10

Defined Benefit Plans (Tables)

Defined Benefit Plans (Tables)	3 Months Ended
	Mar. 31, 2018
Net Periodic Benefit Cost [Member]
Summary of Defined Benefit Plans	Net periodic benefit (income) cost recognized for Company defined benefit pension plans for the three months ended March 31, 2018 and 2017 is as follows: Three Months Ended March 31, 2018 2017 Components of net periodic benefit (income) cost Interest cost 84 89 Expected return on plan assets (141 ) (127 ) Amortization of net actuarial loss 56 61 Net periodic benefit (income) cost $ (1 ) $ 23

Accumulated Other Comprehensi39

Accumulated Other Comprehensive Loss (Tables)	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Components of Accumulated Other Comprehensive Loss	The components of accumulated other comprehensive loss attributable to Fairmount Santrol Holdings Inc. at March 31, 2018 and December 31, 2017 were as follows: March 31, 2018 Gross Tax Effect Net Amount Foreign currency translation $ (10,233 ) $ 1,546 $ (8,687 ) Additional pension liability (3,193 ) 1,220 (1,973 ) Unrealized gain (loss) on interest rate hedges (6,214 ) 2,383 (3,831 ) $ (19,640 ) $ 5,149 $ (14,491 ) December 31, 2017 Gross Tax Effect Net Amount Foreign currency translation $ (10,249 ) $ 1,849 $ (8,400 ) Additional pension liability (3,253 ) 1,220 (2,033 ) Unrealized gain (loss) on interest rate hedges (7,283 ) 2,618 (4,665 ) $ (20,785 ) $ 5,687 $ (15,098 )
Changes in Accumulated Other Comprehensive Loss by Component	The following table presents the changes in accumulated other comprehensive loss by component for the three months ended March 31, 2018: Three Months Ended March 31, 2018 Unrealized Foreign Additional gain (loss) currency pension on interest translation liability rate hedges Total Beginning balance $ (8,400 ) $ (2,033 ) $ (4,665 ) $ (15,098 ) Other comprehensive income before reclassifications (287 ) - - (287 ) Amounts reclassified from accumulated other comprehensive loss - 60 834 894 Ending balance $ (8,687 ) $ (1,973 ) $ (3,831 ) $ (14,491 )
Reclassifications out of Accumulated Other Comprehensive Loss	The following table presents the reclassifications out of accumulated other comprehensive loss during the three months ended March 31, 2018: Amount from accumulated Details about accumulated other other comprehensive Affected line item on comprehensive loss loss the statement of income (loss) Change in fair value of derivative swap agreements Interest rate hedging contracts $ 1,069 Interest expense Tax effect (235 ) Tax $ 834 Net of tax Amortization of pension obligations Actuarial losses $ 60 Cost of sales Total reclassifications for the period $ 894 Net of tax

Segment Reporting (Tables)

Segment Reporting (Tables)	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Summarized Financial Information for Reportable Segments	The chief operating decision maker primarily evaluates an operating segment’s performance based on segment gross profit, which does not include any selling, general, and administrative costs or corporate costs. Three Months Ended March 31, 2018 2017 Revenues Proppant Solutions $ 242,182 $ 140,993 Industrial & Recreational Products 31,156 31,590 Total revenues 273,338 172,583 Segment gross profit Proppant Solutions 76,114 25,461 Industrial & Recreational Products 11,146 12,919 Total segment gross profit 87,260 38,380 Operating expenses excluded from segment gross profit Selling, general, and administrative 27,353 22,470 Depreciation, depletion, and amortization 17,225 17,246 Other operating income (729 ) (1,060 ) Interest expense 13,783 12,537 Income (loss) before provision (benefit) for income taxes $ 29,628 $ (12,813 )

Revenues from Contracts with 41

Revenues from Contracts with Customers (Tables)	3 Months Ended
	Mar. 31, 2018
Revenue From Contract With Customer [Abstract]
Summary of Revenues Disaggregated by Reported Segment and by Product Line	The following table presents the Company’s revenues disaggregated by reportable segment and by product line for the three months ended March 31, 2018 and 2017: Three Months Ended March 31, 2018 Proppant Solutions I&R Total Product lines Raw sand $ 191,176 $ 21,243 $ 212,419 Value-added products 51,006 9,913 60,919 Total revenues $ 242,182 $ 31,156 $ 273,338 Three Months Ended March 31, 2017 Proppant Solutions I&R Total Product lines Raw sand $ 102,834 $ 20,230 $ 123,064 Value-added products 38,159 11,360 49,519 Total revenues $ 140,993 $ 31,590 $ 172,583

Significant Accounting Polici42

Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Significant Of Accounting Policies [Line Items]
Accounts receivable, net of allowance for doubtful accounts	$ 179,234	$ 156,916
Deferred revenue	13,285	8,963
Current Liabilities [Member]
Significant Of Accounting Policies [Line Items]
Deferred revenue	9,346	5,660
Other Long-Term Liabilities [Member]
Significant Of Accounting Policies [Line Items]
Deferred revenue	$ 3,939	$ 3,303
Minimum [Member]
Significant Of Accounting Policies [Line Items]
Accounts receivable payment terms	30 days
Maximum [Member]
Significant Of Accounting Policies [Line Items]
Accounts receivable payment terms	45 days

Significant Accounting Polici43

Significant Accounting Policies - Summary of Changes in Deferred Revenue (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Accounting Policies [Abstract]
Beginning balance	$ 8,963
Deferral of revenue	5,000
Recognition of unearned revenue	(678)
Ending balance	$ 13,285

Revisions of Previously-Issued

Revisions of Previously-Issued Financial Statements - Impact of Revisions on Consolidated Statements of Income (Loss) (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Error Corrections And Prior Period Adjustments Restatement [Line Items]
Revenues	$ 273,338	$ 172,583
Cost of goods sold (excluding depreciation, depletion, and amortization shown separately)	186,078	134,203
Operating expenses
Selling, general and administrative expenses	27,353	22,470
Depreciation, depletion and amortization expense	17,225	17,246
Other operating (income) expense	(729)	(1,060)
Income (loss) from operations	43,411	(276)
Interest expense	13,783	12,537
Income (loss) before provision (benefit) for income taxes	29,628	(12,813)
Provision (benefit) for income taxes	872	(1,160)
Net income (loss)	28,756	(11,653)
Less: Net income attributable to the non-controlling interest	3	178
Net income (loss) attributable to Fairmount Santrol Holdings Inc.	$ 28,753	$ (11,831)
Earnings (loss) per share
Basic	$ 0.13	$ (0.05)
Diluted	$ 0.13	$ (0.05)
Weighted average number of shares outstanding
Basic	224,484	223,739
Diluted	228,940	223,739
ASC 250 [Member]
Error Corrections And Prior Period Adjustments Restatement [Line Items]
Revenues		$ 172,583	$ 959,795	$ 535,013	$ 828,709
Cost of goods sold (excluding depreciation, depletion, and amortization shown separately)		134,203	671,201	469,517	616,020
Operating expenses
Selling, general and administrative expenses		22,470	113,240	79,140	85,191
Depreciation, depletion and amortization expense		17,246	69,410	63,314	60,406
Other operating (income) expense		(1,060)	(1,072)	8,899	979
Goodwill and other asset impairments				89,851	87,476
Restructuring charges				1,155	9,221
Income (loss) from operations		(276)	107,016	(176,863)	(30,584)
Interest expense		12,537	56,408	65,367	62,242
Loss on debt extinguishment, net			2,898
Gain on repurchase of debt, net				(5,110)
Other non-operating income				(10)	1,492
Income (loss) before provision (benefit) for income taxes		(12,813)	47,710	(237,110)	(94,318)
Provision (benefit) for income taxes		(1,160)	(5,715)	(88,630)	(2,103)
Net income (loss)		(11,653)	53,425	(148,480)	(92,215)
Less: Net income attributable to the non-controlling interest		178	297	67	205
Net income (loss) attributable to Fairmount Santrol Holdings Inc.		$ (11,831)	$ 53,128	$ (148,547)	$ (92,420)
Earnings (loss) per share
Basic		$ (0.05)	$ 0.24	$ (0.83)	$ (0.57)
Diluted		$ (0.05)	$ 0.23	$ (0.83)	$ (0.57)
Weighted average number of shares outstanding
Basic		223,739	223,993	179,429	161,297
Diluted		223,739	229,084	179,429	161,297
ASC 250 [Member] | As Reported on 2017 Form 10-K/Q [Member]
Error Corrections And Prior Period Adjustments Restatement [Line Items]
Revenues		$ 172,583	$ 959,795	$ 535,013	$ 828,709
Cost of goods sold (excluding depreciation, depletion, and amortization shown separately)		131,752	659,758	459,714	608,845
Operating expenses
Selling, general and administrative expenses		22,470	113,240	79,140	85,191
Depreciation, depletion and amortization expense		19,442	79,144	72,276	66,754
Other operating (income) expense		(1,060)	(1,072)	8,899	1,357
Goodwill and other asset impairments				93,148	87,476
Restructuring charges				1,155	9,221
Income (loss) from operations		(21)	108,725	(179,319)	(30,135)
Interest expense		12,537	56,408	65,367	62,242
Loss on debt extinguishment, net			2,898
Gain on repurchase of debt, net				(5,110)
Other non-operating income				(10)	1,492
Income (loss) before provision (benefit) for income taxes		(12,558)	49,419	(239,566)	(93,869)
Provision (benefit) for income taxes		(1,148)	(4,666)	(99,441)	(1,939)
Net income (loss)		(11,410)	54,085	(140,125)	(91,930)
Less: Net income attributable to the non-controlling interest		178	297	67	205
Net income (loss) attributable to Fairmount Santrol Holdings Inc.		$ (11,588)	$ 53,788	$ (140,192)	$ (92,135)
Earnings (loss) per share
Basic		$ (0.05)	$ 0.24	$ (0.78)	$ (0.57)
Diluted		$ (0.05)	$ 0.23	$ (0.78)	$ (0.57)
Weighted average number of shares outstanding
Basic		223,739	223,993	179,429	161,297
Diluted		223,739	229,084	179,429	161,297
ASC 250 [Member] | Adjustments [Member]
Error Corrections And Prior Period Adjustments Restatement [Line Items]
Cost of goods sold (excluding depreciation, depletion, and amortization shown separately)		$ 2,451	$ 11,443	$ 9,803	$ 7,175
Operating expenses
Depreciation, depletion and amortization expense		(2,196)	(9,734)	(8,962)	(6,348)
Other operating (income) expense					(378)
Goodwill and other asset impairments				(3,297)
Income (loss) from operations		(255)	(1,709)	2,456	(449)
Income (loss) before provision (benefit) for income taxes		(255)	(1,709)	2,456	(449)
Provision (benefit) for income taxes		(12)	(1,049)	10,811	(164)
Net income (loss)		(243)	(660)	(8,355)	(285)
Net income (loss) attributable to Fairmount Santrol Holdings Inc.		$ (243)	$ (660)	$ (8,355)	$ (285)
Earnings (loss) per share
Basic				$ (0.05)
Diluted				$ (0.05)

Revisions of Previously-Issue45

Revisions of Previously-Issued Financial Statements - Impact of Revisions on Consolidated Statements of Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Error Corrections And Prior Period Adjustments Restatement [Line Items]
Net income (loss)	$ 28,756	$ (11,653)
Other comprehensive income (loss), before tax
Foreign currency translation	16	(39)
Pension obligations	60	61
Change in fair value of derivative agreements	1,069	1,613
Total other comprehensive income, before tax	1,145	1,635
Provision for income taxes related to items of other comprehensive income (loss)	538	1,316
Comprehensive income (loss), net of tax	29,363	(11,334)
Comprehensive income attributable to the non-controlling interest	3	178
Comprehensive income (loss) attributable to Fairmount Santrol Holdings Inc.	$ 29,360	(11,512)
ASC 250 [Member]
Error Corrections And Prior Period Adjustments Restatement [Line Items]
Net income (loss)		(11,653)	$ 53,425	$ (148,480)	$ (92,215)
Other comprehensive income (loss), before tax
Foreign currency translation		(39)	555	(774)	(5,051)
Pension obligations		61	336	425	222
Change in fair value of derivative agreements		1,613	5,863	(3,018)	(1,836)
Total other comprehensive income, before tax		1,635	6,754	(3,367)	(6,665)
Provision for income taxes related to items of other comprehensive income (loss)		1,316	2,850	(2,058)	(1,780)
Comprehensive income (loss), net of tax		(11,334)	57,329	(149,789)	(97,100)
Comprehensive income attributable to the non-controlling interest		178	297	67	205
Comprehensive income (loss) attributable to Fairmount Santrol Holdings Inc.		(11,512)	57,032	(149,856)	(97,305)
ASC 250 [Member] | As Reported on 2017 Form 10-K/Q [Member]
Error Corrections And Prior Period Adjustments Restatement [Line Items]
Net income (loss)		(11,410)	54,085	(140,125)	(91,930)
Other comprehensive income (loss), before tax
Foreign currency translation		(39)	555	(774)	(5,051)
Pension obligations		61	336	425	222
Change in fair value of derivative agreements		1,613	5,863	(3,018)	(1,836)
Total other comprehensive income, before tax		1,635	6,754	(3,367)	(6,665)
Provision for income taxes related to items of other comprehensive income (loss)		1,316	2,850	(2,058)	(1,780)
Comprehensive income (loss), net of tax		(11,091)	57,989	(141,434)	(96,815)
Comprehensive income attributable to the non-controlling interest		178	297	67	205
Comprehensive income (loss) attributable to Fairmount Santrol Holdings Inc.		(11,269)	57,692	(141,501)	(97,020)
ASC 250 [Member] | Adjustments [Member]
Error Corrections And Prior Period Adjustments Restatement [Line Items]
Net income (loss)		(243)	(660)	(8,355)	(285)
Other comprehensive income (loss), before tax
Comprehensive income (loss), net of tax		(243)	(660)	(8,355)	(285)
Comprehensive income (loss) attributable to Fairmount Santrol Holdings Inc.		$ (243)	$ (660)	$ (8,355)	$ (285)

Revisions of Previously-Issue46

Revisions of Previously-Issued Financial Statements - Impact of Revisions on Condensed Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current assets
Cash and cash equivalents	$ 84,768	$ 127,967	$ 210,664	$ 194,069
Accounts receivable, net of allowance for doubtful accounts	179,234	156,916
Inventories, net	64,895	70,528
Prepaid expenses and other assets	7,590	7,765
Total current assets	336,487	363,176
Property, plant and equipment, net	783,429	756,288
Deferred income taxes	351	350
Goodwill	15,301	15,301
Intangibles, net	92,892	93,268
Other assets	10,088	7,711
Total assets	1,238,548	1,236,094
Current liabilities
Current portion of long-term debt	18,924	19,189
Accounts payable	83,852	70,633
Accrued expenses	41,660	74,007
Deferred revenue	9,346	5,660
Total current liabilities	153,782	169,489
Long-term debt	715,316	729,741
Deferred income taxes	6,807	2,429
Other long-term liabilities	36,901	42,189
Total liabilities	912,806	943,848
Commitments and contingent liabilities
Equity
Preferred stock value
Common stock value	2,423	2,423
Additional paid-in capital	294,500	299,912
Retained earnings	318,912	290,159
Accumulated other comprehensive loss	(14,491)	(15,098)
Total equity attributable to Fairmount Santrol Holdings Inc. before treasury stock	601,344	577,396
Less: Treasury stock at cost	(275,975)	(285,520)
Total equity attributable to Fairmount Santrol Holdings Inc.	325,369	291,876
Non-controlling interest	373	370
Total equity	325,742	292,246	215,568	223,734
Total liabilities and equity	$ 1,238,548	1,236,094
ASC 250 [Member]
Current assets
Cash and cash equivalents		127,967	210,664	194,069	$ 171,486	$ 76,923
Accounts receivable, net of allowance for doubtful accounts		156,916		78,942
Inventories, net		70,528		52,650
Prepaid expenses and other assets		6,841		7,065
Refundable income taxes		924		21,077
Total current assets		363,176		353,803
Property, plant and equipment, net		756,288		700,221
Deferred income taxes		350		1,244
Goodwill		15,301		15,301
Intangibles, net		93,268		95,341
Other assets		7,711		9,486
Total assets		1,236,094		1,175,396
Current liabilities
Current portion of long-term debt		19,189		10,707
Accounts payable		70,633		37,263
Accrued expenses		74,007		26,110
Deferred revenue		5,660		75
Total current liabilities		169,489		74,155
Long-term debt		729,741		832,306
Deferred income taxes		2,429		6,929
Other long-term liabilities		42,189		38,272
Total liabilities		943,848		951,662
Commitments and contingent liabilities
Equity
Preferred stock value
Common stock value		2,423		2,422
Additional paid-in capital		299,912		297,649
Retained earnings		290,159		237,466
Accumulated other comprehensive loss		(15,098)		(19,002)
Total equity attributable to Fairmount Santrol Holdings Inc. before treasury stock		577,396		518,535
Less: Treasury stock at cost		(285,520)		(294,874)
Total equity attributable to Fairmount Santrol Holdings Inc.		291,876		223,661
Non-controlling interest		370		73
Total equity		292,246		223,734
Total liabilities and equity		1,236,094		1,175,396
ASC 250 [Member] | As Reported on 2017 Form 10-K/Q [Member]
Current assets
Cash and cash equivalents		127,967	$ 210,664	194,069	$ 171,486	$ 76,923
Accounts receivable, net of allowance for doubtful accounts		156,916		78,942
Inventories, net		70,528		52,650
Prepaid expenses and other assets		6,841		7,065
Refundable income taxes		924		21,077
Total current assets		363,176		353,803
Property, plant and equipment, net		785,513		727,735
Deferred income taxes		350		1,244
Goodwill		15,301		15,301
Intangibles, net		93,268		95,341
Other assets		7,711		9,486
Total assets		1,265,319		1,202,910
Current liabilities
Current portion of long-term debt		19,189		10,707
Accounts payable		70,633		37,263
Accrued expenses		74,007		26,110
Deferred revenue		5,660		75
Total current liabilities		169,489		74,155
Long-term debt		729,741		832,306
Deferred income taxes		3,606		7,057
Other long-term liabilities		42,189		38,272
Total liabilities		945,025		951,790
Commitments and contingent liabilities
Equity
Preferred stock value
Common stock value		2,423		2,422
Additional paid-in capital		299,912		297,649
Retained earnings		318,207		264,852
Accumulated other comprehensive loss		(15,098)		(19,002)
Total equity attributable to Fairmount Santrol Holdings Inc. before treasury stock		605,444		545,921
Less: Treasury stock at cost		(285,520)		(294,874)
Total equity attributable to Fairmount Santrol Holdings Inc.		319,924		251,047
Non-controlling interest		370		73
Total equity		320,294		251,120
Total liabilities and equity		1,265,319		1,202,910
ASC 250 [Member] | Adjustments [Member]
Current assets
Property, plant and equipment, net		(29,225)		(27,514)
Total assets		(29,225)		(27,514)
Current liabilities
Deferred income taxes		(1,177)		(128)
Total liabilities		(1,177)		(128)
Commitments and contingent liabilities
Equity
Preferred stock value
Retained earnings		(28,048)		(27,386)
Total equity attributable to Fairmount Santrol Holdings Inc. before treasury stock		(28,048)		(27,386)
Total equity attributable to Fairmount Santrol Holdings Inc.		(28,048)		(27,386)
Total equity		(28,048)		(27,386)
Total liabilities and equity		$ (29,225)		$ (27,514)

Revisions of Previously-Issue47

Revisions of Previously-Issued Financial Statements - Impact of Revisions on Condensed Consolidated Balance Sheets (Parenthetical) (Detail) - USD ($) $ / shares in Units, $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Error Corrections And Prior Period Adjustments Restatement [Line Items]
Allowance for doubtful accounts	$ 1,237	$ 2,003
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	100,000,000	100,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	1,850,000,000	1,850,000,000
Common Stock, Shares, Issued	242,366,000	242,366,000
Common stock, shares outstanding	224,895,000	224,291,000
Shares in treasury	17,471,000	18,075,000
ASC 250 [Member]
Error Corrections And Prior Period Adjustments Restatement [Line Items]
Allowance for doubtful accounts		$ 2,003	$ 3,055
Preferred stock, par value		$ 0.01	$ 0.01
Preferred stock, shares authorized		100,000,000	100,000,000
Preferred stock, shares outstanding		0	0
Common stock, par value		$ 0.01	$ 0.01
Common stock, shares authorized		1,850,000,000	1,850,000,000
Common Stock, Shares, Issued		242,366,000	242,267,000
Common stock, shares outstanding		224,291,000	223,601,000
Shares in treasury		18,075,000	18,666,000

Revisions of Previously-Issue48

Revisions of Previously-Issued Financial Statements - Impact of Revisions on Condensed Consolidated Statements of Cash Flows (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Error Corrections And Prior Period Adjustments Restatement [Line Items]
Net income (loss)	$ 28,756	$ (11,653)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and depletion	15,198	15,334
Amortization	2,945	3,130
Reserve for doubtful accounts	(764)	(447)
Gain (loss) on disposal of fixed assets	(10)	(714)
Deferred income taxes and taxes payable	3,578	107
Stock compensation expense	3,420	2,416
Change in operating assets and liabilities:
Accounts receivable	(21,554)	(15,956)
Inventories	5,633	(9,038)
Prepaid expenses and other assets	(3,120)	867
Accounts payable	5,613	12,981
Accrued expenses	(33,431)	9,744
Deferred revenue	3,686	16,969
Net cash provided by operating activities	9,851	23,740
Cash flows from investing activities
Proceeds from sale of fixed assets	205	957
Capital expenditures and stripping costs	(37,823)	(4,574)
Net cash used in investing activities	(37,618)	(3,617)
Cash flows from financing activities
Payments on term loans	(4,375)	(2,170)
Payments on capital leases and other long-term debt	(1,163)	(817)
Proceeds from share-based awards exercised or distributed	713	486
Payments on revolving credit facility	(10,000)
Tax payments for withholdings on share-based awards exercised or distributed	(623)	(982)
Transactions with non-controlling interest		(1)
Net cash used in financing activities	(15,448)	(3,484)
Foreign currency adjustment	16	(44)
(Decrease) increase in cash and cash equivalents	(43,199)	16,595
Cash and cash equivalents:
Beginning of period	127,967	194,069	$ 194,069
End of period	84,768	210,664	127,967	$ 194,069
Supplemental disclosure of cash flow information:
Interest paid, net of capitalized interest	14,853	11,717
Income taxes refunded	375	(1,601)
Non-cash investing activities:
Equipment purchased under capital leases		4,175
Decrease in accounts payable for additions to property, plant, and equipment	(7,606)	(1,301)
ASC 250 [Member]
Error Corrections And Prior Period Adjustments Restatement [Line Items]
Net income (loss)		(11,653)	53,425	(148,480)	$ (92,215)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and depletion		15,334	61,663	58,652	55,870
Amortization		3,130	12,784	11,641	11,416
Reserve for doubtful accounts		(447)	(387)	1,851	1,968
Write-off of deferred financing costs			389	2,618	864
Loss on debt extinguishment, gross			2,898
Gain on repurchase of debt, gross				(8,178)
Goodwill and other asset impairments				89,851	76,038
Non-cash restructuring charges					1,162
Inventory write-downs and reserves			1,266	10,302	1,591
Gain (loss) on disposal of fixed assets		(714)	846	420	8,712
Unrealized loss on interest rate swaps			14		49
Deferred income taxes and taxes payable		107	(6,683)	(71,921)	20,819
Stock compensation expense		2,416	10,071	8,870	4,525
Change in operating assets and liabilities:
Accounts receivable		(15,956)	(77,587)	(4,385)	127,718
Inventories		(9,038)	(19,144)	7,543	59,527
Prepaid expenses and other assets		867	(2,398)	11,496	23,234
Refundable income taxes			20,154	5,428	(26,506)
Accounts payable		12,981	18,575	4,196	(38,698)
Accrued expenses		9,744	51,874	11,718	(6,051)
Deferred revenue		16,969	5,585	75
Net cash provided by operating activities		23,740	133,345	(8,303)	230,023
Cash flows from investing activities
Proceeds from sale of fixed assets		957	4,939	5,670
Capital expenditures and stripping costs		(4,574)	(58,130)	(20,794)	(106,953)
Leasehold interest payments for sand reserves			(30,000)
Other investing activities					(250)
Earnout payments			(4,170)	(1,287)
Net cash used in investing activities		(3,617)	(87,361)	(16,411)	(107,203)
Cash flows from financing activities
Proceeds from borrowings on term loan			689,500
Payments on term loans		(2,170)	(6,469)	(10,840)	(13,532)
Prepayments on term loans			(832,655)	(155,926)
Repurchase of term loans				(216,000)
Fees for debt restructure and repurchase of term loans			(2,790)	(450)
Payments on capital leases and other long-term debt		(817)	(4,752)	(5,947)	(6,975)
Proceeds from share-based awards exercised or distributed		486	845	6,438	1,767
Proceeds from borrowing on revolving credit facility			50,000
Payments on revolving credit facility			(5,000)
Proceeds from primary stock offering				439,556
Tax payments for withholdings on share-based awards exercised or distributed		(982)	(1,321)	(8,092)	(826)
Tax effect of share-based awards exercised, forfeited, or expired				(1,100)	(1,472)
Transactions with non-controlling interest		(1)		(842)	(301)
Other financing activities					(4,578)
Net cash used in financing activities		(3,484)	(112,642)	46,797	(25,917)
Change in cash and cash equivalents related to assets classified as held-for-sale				1,376	(1,376)
Foreign currency adjustment		(44)	556	(876)	(964)
(Decrease) increase in cash and cash equivalents		16,595	(66,102)	22,583	94,563
Cash and cash equivalents:
Beginning of period	127,967	194,069	194,069	171,486	76,923
End of period		210,664	127,967	194,069	171,486
ASC 250 [Member] | As Reported on 2017 Form 10-K/Q [Member]
Error Corrections And Prior Period Adjustments Restatement [Line Items]
Net income (loss)		(11,410)	54,085	(140,125)	(91,930)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and depletion		17,530	71,397	67,614	62,218
Amortization		3,130	12,784	11,641	11,416
Reserve for doubtful accounts		(447)	(387)	1,851	1,968
Write-off of deferred financing costs			389	2,618	864
Loss on debt extinguishment, gross			2,898
Gain on repurchase of debt, gross				(8,178)
Goodwill and other asset impairments				93,148	76,038
Non-cash restructuring charges					1,162
Inventory write-downs and reserves			1,266	10,302	1,591
Gain (loss) on disposal of fixed assets		(714)	846	420	8,712
Unrealized loss on interest rate swaps			14		49
Deferred income taxes and taxes payable		119	(5,634)	(82,732)	20,983
Stock compensation expense		2,416	10,071	8,870	4,525
Change in operating assets and liabilities:
Accounts receivable		(15,956)	(77,587)	(4,385)	127,718
Inventories		(9,038)	(19,144)	7,543	59,527
Prepaid expenses and other assets		(1,078)	(2,398)	11,496	23,234
Refundable income taxes		1,945	20,154	5,428	(26,506)
Accounts payable		12,981	18,575	4,196	(38,698)
Accrued expenses and deferred revenue		26,489
Accrued expenses			51,874	11,718	(6,051)
Deferred revenue			5,585	75
Net cash provided by operating activities		25,967	144,788	1,500	236,820
Cash flows from investing activities
Proceeds from sale of fixed assets		957	4,939	5,670
Capital expenditures and stripping costs		(7,025)	(69,573)	(30,597)	(113,750)
Leasehold interest payments for sand reserves			(30,000)
Other investing activities		(758)			(250)
Earnout payments			(4,170)	(1,287)
Net cash used in investing activities		(6,826)	(98,804)	(26,214)	(114,000)
Cash flows from financing activities
Proceeds from borrowings on term loan			689,500
Payments on term loans		(2,170)	(6,469)	(10,840)	(13,532)
Prepayments on term loans			(832,655)	(155,926)
Repurchase of term loans				(216,000)
Fees for debt restructure and repurchase of term loans			(2,790)	(450)
Payments on capital leases and other long-term debt		(817)	(4,752)	(5,947)	(6,975)
Proceeds from share-based awards exercised or distributed		486	845	6,438	1,767
Proceeds from borrowing on revolving credit facility			50,000
Payments on revolving credit facility			(5,000)
Proceeds from primary stock offering				439,556
Tax payments for withholdings on share-based awards exercised or distributed			(1,321)	(8,092)	(826)
Tax effect of share-based awards exercised, forfeited, or expired				(1,100)	(1,472)
Transactions with non-controlling interest		(1)		(842)	(301)
Other financing activities					(4,578)
Net cash used in financing activities		(2,502)	(112,642)	46,797	(25,917)
Change in cash and cash equivalents related to assets classified as held-for-sale				1,376	(1,376)
Foreign currency adjustment		(44)	556	(876)	(964)
(Decrease) increase in cash and cash equivalents		16,595	(66,102)	22,583	94,563
Cash and cash equivalents:
Beginning of period	$ 127,967	194,069	194,069	171,486	76,923
End of period		210,664	127,967	194,069	171,486
Supplemental disclosure of cash flow information:
Interest paid, net of capitalized interest		11,717	59,498	60,833	61,395
Income taxes refunded		(1,601)	(19,278)	(21,311)	(19,898)
Non-cash investing activities:
Equipment purchased under capital leases		4,175	10,988		4,552
Decrease in accounts payable for additions to property, plant, and equipment		(1,301)	(14,796)
Increase in accounts payable for additions to property, plant, and equipment				8,100	652
ASC 250 [Member] | Adjustments [Member]
Error Corrections And Prior Period Adjustments Restatement [Line Items]
Net income (loss)		(243)	(660)	(8,355)	(285)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and depletion		(2,196)	(9,734)	(8,962)	(6,348)
Goodwill and other asset impairments				(3,297)
Deferred income taxes and taxes payable		(12)	(1,049)	10,811	(164)
Change in operating assets and liabilities:
Prepaid expenses and other assets		1,945
Refundable income taxes		(1,945)
Accrued expenses and deferred revenue		(26,489)
Accrued expenses		9,744
Deferred revenue		16,969
Net cash provided by operating activities		(2,227)	(11,443)	(9,803)	(6,797)
Cash flows from investing activities
Capital expenditures and stripping costs		2,451	11,443	9,803	6,797
Other investing activities		758
Net cash used in investing activities		3,209	$ 11,443	$ 9,803	$ 6,797
Cash flows from financing activities
Tax payments for withholdings on share-based awards exercised or distributed		(982)
Net cash used in financing activities		$ (982)

Inventories, net - Schedule of

Inventories, net - Schedule of Inventories (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Raw materials	$ 8,368	$ 7,412
Work-in-process	10,303	14,819
Finished goods	46,848	48,931
Inventory gross	65,519	71,162
Less: LIFO reserve	(624)	(634)
Inventories, net	$ 64,895	$ 70,528

Property, Plant, and Equipmen50

Property, Plant, and Equipment, net - Schedule of Property, Plant, and Equipment (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	$ 1,184,840	$ 1,142,472
Accumulated depletion and depreciation	(401,411)	(386,184)
Property, plant, and equipment, net	783,429	756,288
Land and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	83,491	85,012
Mineral Reserves and Mine Development [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	228,356	222,271
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	601,745	590,584
Buildings and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	186,631	186,466
Furniture, Fixtures and Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	3,492	3,478
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	$ 81,125	$ 54,661

Property, Plant, and Equipmen51

Property, Plant, and Equipment, net - Additional Information (Detail) $ in Thousands	Jul. 18, 2017USD ($)a	Oct. 31, 2017USD ($)	Mar. 31, 2018USD ($)
Property, Plant and Equipment [Line Items]
Term of lease agreement	40 years
Area of sand reserves under lease agreement | a	3,250
Initial payment made at lease commencement	$ 20,000
Operating lease installment payment		$ 10,000
Contingent leasehold Interest payments			$ 10,000
Mineral Reserves And Mine Development [Member]
Property, Plant and Equipment [Line Items]
Capitalization of leasehold interest obligation and related exploratory and transaction costs	$ 40,000

Long-Term Debt - Schedule of Lo

Long-Term Debt - Schedule of Long-Term Debt (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Term Loan B	$ 685,184	$ 688,990
Industrial Revenue Bond	10,000	10,000
ABL Revolver, Revolving Credit Facility, and other	35,056	45,073
Capital leases, net	8,738	9,884
Long term debt	734,240	748,930
Less: current portion	(18,924)	(19,189)
Long-term debt including leases	715,316	729,741
Term Loans [Member]
Debt Instrument [Line Items]
Deferred financing costs, net	$ (4,738)	$ (5,017)

Long-Term Debt - Additional Inf

Long-Term Debt - Additional Information (Detail) - USD ($)	Nov. 01, 2017	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Available capacity remaining on the revolving credit facility		$ 74,099,000
Outstanding letters of credit		15,290,000
Amount withheld for collateral		$ 611,000
Industrial Revenue Bond [Member]
Debt Instrument [Line Items]
Debt instrument borrowings, maturity date		Sep. 1, 2027
Debt instrument, interest rate		1.65%	1.46%
Debt instrument face amount		$ 10,000,000
Letter of credit		$ 10,000,000
Barclays Capital Inc [Member] | Term Loan B [Member]
Debt Instrument [Line Items]
Debt instrument, frequency of periodic payment		quarterly
Debt instrument borrowings, maturity date	Nov. 1, 2022
Debt instrument principal amount	$ 700,000,000
Debt instrument original issued discount percentage	98.50%
Percentage of annual amortization payments in principal amount for first half of loan period	2.50%
Percentage of annual amortization payments in principal amount for second half of loan period	5.00%
Debt instrument, description of variable rate basis		three-month LIBOR plus 6.0% with a LIBOR floor of 1.0%
Debt instrument refinance description		Should the Company choose to refinance the Term Loan B, it would be subject to a 1.02% premium if refinanced at a lower interest rate within one year of the Closing Date or a 1.01% premium if refinanced at a lower interest rate within two years of the Closing Date.
Percentage of premium for refinance within one year of closing date	1.02%
Percentage of premium for refinance within two years of closing date	1.01%
Change in control description		In the event of a change in control of 35% or more of the voting interests of the Company and at the request of the lenders, the unpaid principal and interest of the Term Loan B may become immediately due and payable.
Debt instrument, interest rate		8.30%	7.70%
Minimum [Member] | Barclays Capital Inc [Member] | Term Loan B [Member]
Debt Instrument [Line Items]
Voting interests	35.00%
LIBOR [Member] | Barclays Capital Inc [Member] | Term Loan B [Member]
Debt Instrument [Line Items]
Applicable margin on interest rate	6.00%
Debt instrument floor rate	1.00%
ABL Revolver [Member] | PNC Capital Markets LLC [Member]
Debt Instrument [Line Items]
Debt instrument term	5 years
Line of credit facility maximum borrowing capacity	$ 125,000,000
Line of credit facility increasing amount	50,000,000
Line of credit facility option to increase maximum borrowing capacity	175,000,000
Proceeds from revolving credit facility	$ 50,000,000
Debt instrument, frequency of periodic payment		quarterly
Debt instrument, maturity date, description		If the Term Loan B is still outstanding, then any balance outstanding under the ABL Revolver is due on May 1, 2022.
Minimum fixed charge coverage ratio	110.00%
Debt instrument, interest rate		3.60%	3.30%
Available capacity remaining on the revolving credit facility		$ 90,000,000
ABL Revolver [Member] | PNC Capital Markets LLC [Member] | If Term Loan B Not Outstanding [Member]
Debt Instrument [Line Items]
Debt instrument borrowings, maturity date	Nov. 1, 2022
ABL Revolver [Member] | PNC Capital Markets LLC [Member] | If Term Loan B Still Outstanding [Member]
Debt Instrument [Line Items]
Debt instrument borrowings, maturity date	May 1, 2022
ABL Revolver [Member] | LIBOR [Member] | Minimum [Member] | PNC Capital Markets LLC [Member]
Debt Instrument [Line Items]
Applicable margin on interest rate	1.50%
ABL Revolver [Member] | LIBOR [Member] | Maximum [Member] | PNC Capital Markets LLC [Member]
Debt Instrument [Line Items]
Applicable margin on interest rate	2.00%
ABL Revolver [Member] | Federal Funds Open Rate [Member] | PNC Capital Markets LLC [Member]
Debt Instrument [Line Items]
Applicable margin on interest rate	0.50%
ABL Revolver [Member] | Daily LIBOR [Member] | PNC Capital Markets LLC [Member]
Debt Instrument [Line Items]
Applicable margin on interest rate	1.00%

Accrued Expenses - Summary of A

Accrued Expenses - Summary of Accrued Expenses (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Payables And Accruals [Abstract]
Accrued payroll and fringe benefits	$ 8,526	$ 11,233
Accrued bonus	3,543	37,166
Accrued income taxes	386	504
Accrued real estate taxes	4,617	5,098
Accrued leasehold interest payments	10,000	10,000
Other accrued expenses	14,588	10,006
Accrued expenses	$ 41,660	$ 74,007

Earnings (Loss) per Share - Com

Earnings (Loss) per Share - Computation of Basic and Diluted Earnings (Loss) per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Numerator:
Net income (loss) attributable to Fairmount Santrol Holdings Inc.	$ 28,753	$ (11,831)
Denominator:
Basic weighted average shares outstanding	224,484,000	223,739,000
Dilutive effect of employee stock options, RSUs, and PRSUs	4,456,000	0
Diluted weighted average shares outstanding	228,940,000	223,739,000
Earnings (loss) per common share – basic	$ 0.13	$ (0.05)
Earnings (loss) per common share – diluted	$ 0.13	$ (0.05)

Earnings (Loss) per Share - Add

Earnings (Loss) per Share - Additional Information (Detail) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Securities excluded from computation of earning per share	6,170	4,739

Derivative Instruments - Additi

Derivative Instruments - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2018USD ($)Agreement	Dec. 31, 2017USD ($)	Nov. 30, 2017USD ($)
Derivative [Line Items]
Number of interest rate swap agreements | Agreement	1
Interest Rate Swap Agreements [Member]
Derivative [Line Items]
Notional amount of swap agreements	$ 210,000,000	$ 210,000,000
Notional amount as percent of term debt outstanding	30.00%	30.00%
Interest rate swap agreement, maturity date	Sep. 5, 2019
Derivative variable interest rate	2.92%
Notional amount of swap agreements, terminated			$ 210,000,000
Interest Rate Swap Agreements [Member] | Interest Expense [Member]
Derivative [Line Items]
Reclassification from Accumulated other comprehensive income (loss)	$ 4,333,000
Reclassification from accumulated other comprehensive income (loss), estimate of time to transfer	12 months

Derivative Instruments - Fair V

Derivative Instruments - Fair Values of Derivative Instrument and Respective Classification in Condensed Consolidated Balance Sheets (Detail) - Interest Rate Swap Agreements [Member] - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivative, fair value	$ (1,394)	$ (3,208)
Non-Qualifying Cash Flow Hedge [Member] | Other Long-Term Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	$ (1,394)	$ (3,208)

Derivative Instruments - Schedu

Derivative Instruments - Schedule of Interest Expense Derivatives (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Derivatives, Fair Value [Line Items]
Interest expense	$ (13,783)	$ (12,537)
Interest Rate Swap Agreements [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member] | Designated as Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Interest expense		(77)
Interest Rate Swap Agreements [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member] | Derivatives Not Designated as Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Interest expense	(99)
Interest Rate Swap Agreements [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member] | Interest Income Expense [Member] | Designated as Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Interest expense		$ (77)
Interest Rate Swap Agreements [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member] | Interest Income Expense [Member] | Derivatives Not Designated as Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Interest expense	$ (99)

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Fair Value for Long-term Debt (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of long term debt	$ 704,320	$ 708,750
Term Loan B [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of long term debt	704,320	708,750
Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of long term debt	704,320	708,750
Other Observable Inputs (Level 2) [Member] | Term Loan B [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of long term debt	$ 704,320	$ 708,750

Fair Value Measurements - Finan

Fair Value Measurements - Financial Instruments Carried at Fair Value (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Interest Rate Swap Agreements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap agreements	$ (1,394)	$ (3,208)
Recurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Net Asset (Liability)	(1,394)	(3,208)
Recurring Fair Value Measurements [Member] | Interest Rate Swap Agreements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap agreements	(1,394)	(3,208)
Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Net Asset (Liability)	(1,394)	(3,208)
Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member] | Interest Rate Swap Agreements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap agreements	$ (1,394)	$ (3,208)

Common Stock and Stock Based Co

Common Stock and Stock Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted to purchase		443
Average grant date fair value of options issued		$ 10.03
Stock compensation expense	$ 3,420	$ 2,416
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock units issued	1,581	366
Performance Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock units issued		139

Common Stock and Stock Based 63

Common Stock and Stock Based Compensation - Summary of Share Based Compensation Activity of Option and Non-option Instruments (Detail) - $ / shares shares in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, Outstanding Beginning Balance	13,393
Options, Granted		443
Options, Exercised	(355)
Options, Forfeited	(9)
Options, Expired	(4)
Options, Outstanding Ending Balance	13,025
Weighted Average Exercise Price, Options, Outstanding Beginning Balance	$ 6.63
Weighted Average Exercise Price, Options, Exercised	2.58
Weighted Average Exercise Price, Options, Forfeited	10.70
Weighted Average Exercise Price, Options, Expired	16
Weighted Average Exercise Price, Options, Outstanding Ending Balance	$ 6.73
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding Beginning Balance	1,517
Granted	1,581
Exercised	(280)
Forfeited	(6)
Outstanding Ending Balance	2,812
Weighted Average Price at Issue Date, Outstanding Beginning Balance	$ 6.63
Weighted Average Price at Issue Date, Granted	4.56
Weighted Average Price at Issue Date, Exercised	4.65
Weighted Average Price at Issue Date, Forfeited	10.03
Weighted Average Price at Issue Date, Outstanding Ending Balance	$ 5.67
Performance Restricted Stock Units (PRSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding Beginning Balance	584
Outstanding Ending Balance	584
Weighted Average Price at Issue Date, Outstanding Beginning Balance	$ 4.10
Weighted Average Price at Issue Date, Outstanding Ending Balance	$ 4.10

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Provision (benefit) for income taxes	$ 872	$ (1,160)
Income (Loss) before income taxes	$ 29,628	$ (12,813)
Effective income tax rate	2.90%	9.10%
Corporate income tax rate	21.00%
Tax Act 2017, one-time transition tax on unremitted foreign earnings	$ 3,046

Defined Benefit Plans - Additio

Defined Benefit Plans - Additional Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)Pension_Plan	Mar. 31, 2017USD ($)
Compensation And Retirement Disclosure [Abstract]
Number of defined benefit pension plans | Pension_Plan	2
Pension and postretirement contributions	$ 0	$ 19
Expected contribution for pension plan remaining fiscal year	$ 28

Defined Benefit Plans - Summary

Defined Benefit Plans - Summary of Defined Benefit Plans (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Compensation And Retirement Disclosure [Abstract]
Interest cost	$ 84	$ 89
Expected return on plan assets	(141)	(127)
Amortization of net actuarial loss	56	61
Net periodic benefit (income) cost	$ (1)	$ 23

Accumulated Other Comprehensi67

Accumulated Other Comprehensive Loss - Components of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, Gross	$ (19,640)	$ (20,785)
Accumulated other comprehensive loss, Tax Effect	5,149	5,687
Accumulated other comprehensive loss	(14,491)	(15,098)
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, Gross	(10,233)	(10,249)
Accumulated other comprehensive loss, Tax Effect	1,546	1,849
Accumulated other comprehensive loss	(8,687)	(8,400)
Additional Pension Liability [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, Gross	(3,193)	(3,253)
Accumulated other comprehensive loss, Tax Effect	1,220	1,220
Accumulated other comprehensive loss	(1,973)	(2,033)
Unrealized Gain (Loss) on Interest Rate Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, Gross	(6,214)	(7,283)
Accumulated other comprehensive loss, Tax Effect	2,383	2,618
Accumulated other comprehensive loss	$ (3,831)	$ (4,665)

Accumulated Other Comprehensi68

Accumulated Other Comprehensive Loss - Changes in Accumulated Other Comprehensive Loss by Component (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balances	$ 292,246
Other comprehensive income before reclassifications	(287)
Amounts reclassified from accumulated other comprehensive loss	894
Ending balances	325,742
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balances	(8,400)
Other comprehensive income before reclassifications	(287)
Ending balances	(8,687)
Additional Pension Liability [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balances	(2,033)
Amounts reclassified from accumulated other comprehensive loss	60
Ending balances	(1,973)
Unrealized Gain (Loss) on Interest Rate Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balances	(4,665)
Amounts reclassified from accumulated other comprehensive loss	834
Ending balances	(3,831)
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balances	(15,098)
Ending balances	$ (14,491)

Accumulated Other Comprehensi69

Accumulated Other Comprehensive Loss - Reclassifications out of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ 13,783	$ 12,537
Income (loss) before provision (benefit) for income taxes	29,628	(12,813)
Tax expense	(872)	1,160
Net income (loss)	28,756	(11,653)
Cost of sales	186,078	$ 134,203
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income (loss)	894
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member] | Unrealized Gain (Loss) on Interest Rate Hedges [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	1,069
Tax expense	(235)
Net income (loss)	834
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member] | Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of sales	$ 60

Commitments and Contingent Li70

Commitments and Contingent Liabilities - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 17, 2015	Mar. 31, 2018	Mar. 31, 2017
Commitments and Contingencies [Line Items]
Contingent leasehold Interest payments		$ 10,000
Rent expense for lease		$ 13,127	$ 13,714
Self-Suspending Proppant LLC [Member]
Commitments and Contingencies [Line Items]
Commitment period of sales		5 years
Commitment commencing date		Oct. 1, 2015
Threshold aggregate earnout payment from the two-year period ending October 1, 2017 until the three-year period ending October 1, 2018	$ 45,000
Threshold aggregate earnout payment during the two-year period ending October 1, 2017	$ 15,000
Security interest percentage of equity in contingent consideration	51.00%
Asset acquisition contingent consideration	$ 195,000
Estimated earnout payments capitalized		$ 11,119
Disbursement of earnout payments		5,457
Accrued earnout liability		$ 5,662

Transactions with Related Par71

Transactions with Related Parties - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
American Securities [Member]
Related Party Transaction [Line Items]
Management fees and expense payment	$ 47	$ 86

Segment Reporting - Additional

Segment Reporting - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2018SegmentCustomer	Mar. 31, 2017Customer
Segment Reporting Information [Line Items]
Number of reportable segments | Segment	2
Number of customers | Customer	3	3
Customer Concentration Risk [Member] | Revenues [Member] | Customer One [Member]
Segment Reporting Information [Line Items]
Consolidated net revenues	29.00%	24.00%
Customer Concentration Risk [Member] | Revenues [Member] | Customer Two [Member]
Segment Reporting Information [Line Items]
Consolidated net revenues	11.00%	12.00%
Customer Concentration Risk [Member] | Revenues [Member] | Customer Three [Member]
Segment Reporting Information [Line Items]
Consolidated net revenues	10.00%	11.00%

Segment Reporting - Summarized

Segment Reporting - Summarized Financial Information for Reportable Segments (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenues
Revenues	$ 273,338	$ 172,583
Segment gross profit
Segment gross profit	87,260	38,380
Operating expenses excluded from segment gross profit
Selling, general, and administrative	27,353	22,470
Depreciation, depletion, and amortization	17,225	17,246
Other operating income	(729)	(1,060)
Interest expense	13,783	12,537
Income (loss) before provision (benefit) for income taxes	29,628	(12,813)
Proppant Solutions [Member]
Revenues
Revenues	242,182	140,993
Segment gross profit
Segment gross profit	76,114	25,461
Industrial & Recreational Products [Member]
Revenues
Revenues	31,156	31,590
Segment gross profit
Segment gross profit	$ 11,146	$ 12,919

Goodwill and Intangibles - Addi

Goodwill and Intangibles - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Goodwill [Line Items]
Goodwill	$ 15,301	$ 15,301
FTSI Supply Agreement [Member]
Goodwill [Line Items]
Intangible asset, net of accumulated amortization	29,659
SSP Technology [Member]
Goodwill [Line Items]
Intangible asset, net of accumulated amortization	63,225
Industrial & Recreational Products [Member]
Goodwill [Line Items]
Goodwill	$ 15,301

Revenues from Contracts with 75

Revenues from Contracts with Customers - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Disaggregation Of Revenue [Line Items]
Accounts receivable related to shortfall payments	$ 0	$ 0
Minimum [Member]
Disaggregation Of Revenue [Line Items]
Contracts with customers term	1 year
Maximum [Member]
Disaggregation Of Revenue [Line Items]
Contracts with customers term	8 years

Revenues from Contracts with 76

Revenues from Contracts with Customers - Summary of Revenues Disaggregated by Reported Segment and by Product Line (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation Of Revenue [Line Items]
Total revenues	$ 273,338	$ 172,583
Raw Sand [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	212,419	123,064
Value-added Products [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	60,919	49,519
Proppant Solutions [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	242,182	140,993
Proppant Solutions [Member] | Raw Sand [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	191,176	102,834
Proppant Solutions [Member] | Value-added Products [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	51,006	38,159
Industrial & Recreational Products [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	31,156	31,590
Industrial & Recreational Products [Member] | Raw Sand [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	21,243	20,230
Industrial & Recreational Products [Member] | Value-added Products [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	$ 9,913	$ 11,360

Proposed Merger with Unimin C77

Proposed Merger with Unimin Corporation - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 11, 2017	Mar. 31, 2018
Business Acquisition [Line Items]
Expenses associated with merger		$ 3,334
Selling, General and Administrative Expenses [Member]
Business Acquisition [Line Items]
Expenses associated with merger	$ 11,645
Merger Agreement [Member] | Unimin [Member]
Business Acquisition [Line Items]
Payments to acquire businesses, net of cash acquired	$ 170,000
Business acquisition percentage of common stock	35.00%
Business acquisition remaining percentage of common stock.	65.00%
Merger agreement termination fee payable upon exercise of conditional termination rights	$ 52,000