CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Preferred Stock	Common stock	Treasury Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income	Non-Controlling Interest
Beginning balance at Dec. 31, 2015	$ 443,903	$ 0	$ 5	$ (2,397)	$ 472,494	$ (20,640)	$ (5,559)	$ 0
Beginning balance (in shares) at Dec. 31, 2015		1	49,940,548
Increase (Decrease) in Stockholders' Equity [Abstract]
Stock-based compensation	3,250				3,250
Transfer of director compensation from liability to equity	185				185
Issuance of stock, net of forfeitures (in shares)			813,073
Shares withheld for taxes	(331)				(331)
Shares withheld for taxes (in shares)			(55,034)
Repurchase of stock for treasury	(1,488)			(1,488)
Comprehensive income (loss)	(110,374)					(111,560)	1,186
Ending balance at Dec. 31, 2016	335,145	$ 0	$ 5	(3,885)	475,598	(132,200)	(4,373)	0
Ending balance (in shares) at Dec. 31, 2016		1	50,698,587
Increase (Decrease) in Stockholders' Equity [Abstract]
Stock-based compensation	1,886				1,886
Transfer of director compensation from liability to equity	442				442
Issuance of stock, net of forfeitures (in shares)			303,647
Settlement of Dow liabilities	55,089				55,089
Purchase of Non-controlling interest	8,352							8,352
Comprehensive income (loss)	15,166					23,471	(8,396)	91
Ending balance at Dec. 31, 2017	416,080	$ 0	$ 5	(3,885)	533,015	(108,729)	(12,769)	8,443
Ending balance (in shares) at Dec. 31, 2017		1	51,002,234
Increase (Decrease) in Stockholders' Equity [Abstract]
Stock-based compensation	2,804				2,804
Issuance of stock, net of forfeitures (in shares)			69,339
Comprehensive income (loss)	(46,308)					(30,060)	(16,068)	(180)
Ending balance at Dec. 31, 2018	$ 372,576	$ 0	$ 5	$ (3,885)	$ 535,819	$ (138,789)	$ (28,837)	$ 8,263
Ending balance (in shares) at Dec. 31, 2018		1	51,071,573