CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Revenues	$ 53,819	$ 50,173	$ 161,175	$ 128,415
Cost of sales (exclusive of depreciation and amortization shown below)	50,514	53,805	152,303	142,830
Depreciation and amortization	8,058	10,891	24,793	32,999
Gross loss	(4,753)	(14,523)	(15,921)	(47,414)
Selling, general and administrative expenses (exclusive of depreciation and amortization shown below)	10,121	9,494	30,412	29,272
Depreciation and amortization	625	641	1,859	1,924
Loss on sale of Russian proppant business	0	26,728	350	26,728
Other operating (income) expense	(718)	125,738	(777)	125,738
Operating loss	(14,781)	(177,124)	(47,765)	(231,076)
Other expense:
Interest expense, net	(2,292)	(1,915)	(6,393)	(5,630)
Other, net	166	258	173	448
Nonoperating income (expense), total	(2,126)	(1,657)	(6,220)	(5,182)
Loss before income taxes	(16,907)	(178,781)	(53,985)	(236,258)
Income tax benefit	(171)	(316)	(164)	(527)
Net loss	$ (16,736)	$ (178,465)	$ (53,821)	$ (235,731)
Loss per share:
Basic	$ (0.62)	$ (6.69)	$ (2.00)	$ (8.84)
Diluted	(0.62)	(6.69)	(2.00)	(8.84)
Other information:
Dividends declared per common share	$ 0	$ 0	$ 0	$ 0