CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating activities
Net loss	$ (235,731,000)	$ (64,930,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	35,805,000	36,499,000
Provision for doubtful accounts	493,000	1,202,000
Deferred income taxes	76,000	(35,275,000)
Lower of cost or market inventory adjustment	0	115,000
Loss on disposal or impairment of assets	125,738,000	910,000
Loss on sale of Russian proppant business	25,101,000	0
Foreign currency transaction gain, net	(35,000)	(147,000)
Stock compensation expense	3,831,000	4,814,000
PIK accrual on notes payable, related parties	997,000	0
Change in fair value of derivative instruments	(575,000)	(4,640,000)
Changes in operating assets and liabilities:
Trade accounts and other receivables	(14,538,000)	28,379,000
Inventories	5,567,000	992,000
Prepaid expenses and other current assets	(245,000)	1,508,000
Accounts payable	8,795,000	(4,430,000)
Accrued expenses	3,561,000	(8,338,000)
Income tax receivable, net	(1,069,000)	37,046,000
Other, net	2,123,000	1,010,000
Net cash used in by operating activities	(40,106,000)	(5,285,000)
Investing activities
Capital expenditures	(1,748,000)	(6,554,000)
Net proceeds from sale of Russian proppant business	21,154,000	0
Net cash provided by (used in) investing activities	19,406,000	(6,554,000)
Financing activities
Proceeds from long-term debt	12,349,000	0
Repayments on long-term debt	(3,250,000)	(29,066,000)
Repayments on insurance financing agreement	(923,000)	(458,000)
Payments of debt issuance costs	(989,000)	(339,000)
Proceeds from notes payable, related parties	0	25,000,000
Purchase of common stock	(534,000)	(443,000)
Net cash provided by financing activities	6,653,000	40,258,000
Effect of exchange rate changes on cash	246,000	714,000
Net (decrease) increase in cash and cash equivalents and restricted cash	(13,801,000)	29,133,000
Cash and cash equivalents and restricted cash at beginning of period	91,680,000	78,866,000
Cash and cash equivalents and restricted cash at end of period	77,879,000	107,999,000
Supplemental cash flow information
Interest paid	2,319,000	3,456,000
Income taxes paid	465,000	0
ATM Program
Financing activities
Proceeds from sale of common stock under ATM program	$ 0	$ 45,564,000