Unaudited Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings (Accumulated Deficit)	Non-controlling Interests
Increase (Decrease) in Equity [Roll Forward]
Beginning balance (in shares)		(60,623,000)	3,621,000
Ending balance (in shares)		(60,623,000)	3,621,000
Beginning balance at Dec. 31, 2017	$ 265,258	$ 6	$ (33,064)	$ 336,067	$ (884)	$ (37,225)	$ 358
Increase (Decrease) in Equity [Roll Forward]
Net income (loss)	(75,324)					(74,967)	(357)
Foreign currency translation adjustment	(161)				(161)
Stock issued under employee stock purchase plan (in shares)			65,000
Stock issued under employee stock purchase plan	247			247
Restricted stock granted (in shares)		1,019,000
Restricted stock forfeited (in shares)			45,000
Treasury stock purchased (in shares)			6,000
Treasury stock purchased	(24)		$ (24)
Stock compensation expense	4,304			4,304
Ending balance at Jun. 30, 2018	194,300	$ 6	$ (33,088)	340,618	(1,045)	(112,192)	1
Increase (Decrease) in Equity [Roll Forward]
Beginning balance (in shares)		(61,161,000)	3,599,000
Ending balance (in shares)		(61,161,000)	3,599,000
Beginning balance at Mar. 31, 2018	267,213	$ 6	$ (33,067)	338,137	(1,063)	(37,158)	358
Increase (Decrease) in Equity [Roll Forward]
Net income (loss)	(75,391)					(75,034)	(357)
Foreign currency translation adjustment	18				18
Stock issued under employee stock purchase plan (in shares)			36,000
Stock issued under employee stock purchase plan	100			100
Restricted stock granted (in shares)		481,000
Restricted stock forfeited (in shares)			39,000
Treasury stock purchased (in shares)			5,000
Treasury stock purchased	(21)		$ (21)
Stock compensation expense	2,381			2,381
Ending balance at Jun. 30, 2018	194,300	$ 6	$ (33,088)	340,618	(1,045)	(112,192)	1
Increase (Decrease) in Equity [Roll Forward]
Beginning balance (in shares)		(61,642,000)	3,607,000
Ending balance (in shares)		(61,642,000)	3,607,000
Beginning balance (in shares)		(62,163,000)	3,770,000
Ending balance (in shares)		(62,163,000)	3,770,000
Beginning balance at Dec. 31, 2018	201,624	$ 6	$ (33,237)	343,536	(1,116)	(107,565)	0
Increase (Decrease) in Equity [Roll Forward]
Net income (loss)	18,394					18,394
Foreign currency translation adjustment	$ 118				118
Restricted stock granted (in shares)	792,997	793,000
Restricted stock forfeited (in shares)			133,000
Treasury stock purchased (in shares)			45,000
Treasury stock purchased	$ (141)		$ (141)
Stock compensation expense	1,681			1,681
Ending balance at Jun. 30, 2019	221,676	$ 6	$ (33,378)	345,217	(998)	(89,171)	0
Increase (Decrease) in Equity [Roll Forward]
Beginning balance (in shares)		(62,199,000)	3,845,000
Ending balance (in shares)		(62,199,000)	3,845,000
Beginning balance at Mar. 31, 2019	235,047	$ 6	$ (33,368)	344,004	(1,022)	(74,573)	0
Increase (Decrease) in Equity [Roll Forward]
Net income (loss)	(14,598)					(14,598)
Foreign currency translation adjustment	24				24
Restricted stock granted (in shares)		757,000
Restricted stock forfeited (in shares)			99,000
Treasury stock purchased (in shares)			4,000
Treasury stock purchased	(10)		$ (10)
Stock compensation expense	1,213			1,213
Ending balance at Jun. 30, 2019	$ 221,676	$ 6	$ (33,378)	$ 345,217	$ (998)	$ (89,171)	$ 0
Increase (Decrease) in Equity [Roll Forward]
Beginning balance (in shares)		(62,956,000)	3,948,000
Ending balance (in shares)		(62,956,000)	3,948,000