CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands	Total	Common Stock	[1]	Additional Paid-In Capital	[1]	Accumulated Deficit	Treasury Stock
Balance at Dec. 31, 2018	$ 1,212,098	$ 4		$ 1,771,936		$ (559,842)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock activity and shares exchanged for tax withholding	(1,724)			1			(1,725)
Stock-based compensation	6,214			6,214
Retirement of treasury stock	0			(1,725)			1,725
Net income (loss)	(87,025)					(87,025)
Balance at Sep. 30, 2019	1,129,563	4		1,776,426		(646,867)	0
Balance at Jun. 30, 2019	1,116,393	4		1,774,370		(657,981)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock activity and shares exchanged for tax withholding	(218)			1			(219)
Stock-based compensation	2,274			2,274
Retirement of treasury stock	0			(219)			219
Net income (loss)	11,114					11,114
Balance at Sep. 30, 2019	1,129,563	4		1,776,426		(646,867)	0
Balance at Dec. 31, 2019	1,083,318	4		1,777,986		(694,672)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock activity and shares exchanged for tax withholding	(667)			1			(668)
Stock-based compensation	3,806			3,806
Retirement of treasury stock	0			(668)			668
Net income (loss)	(1,099,072)					(1,099,072)
Balance at Sep. 30, 2020	(12,615)	4		1,781,125		(1,793,744)	0
Balance at Jun. 30, 2020	2,179	4		1,780,114		(1,777,939)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock activity and shares exchanged for tax withholding	(14)						(14)
Stock-based compensation	1,025			1,025
Retirement of treasury stock	0			(14)			14
Net income (loss)	(15,805)					(15,805)
Balance at Sep. 30, 2020	$ (12,615)	$ 4		$ 1,781,125		$ (1,793,744)	$ 0

[1] Amounts have been retroactively adjusted to reflect a 1-for-50 reverse stock split effective October 30, 2020. See Note 12 for additional information.