CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings (Accumulated Deficit)	Treasury Stock
Balance at Dec. 31, 2018	$ 1,212,098	$ 210	$ 1,771,730	$ (559,842)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock activity and shares exchanged for tax withholding	(1,484)				(1,484)
Stock-based compensation	2,090		2,090
Retirement of treasury stock	0		(1,484)		1,484
Net income (loss)	(96,229)			(96,229)
Balance at Mar. 31, 2019	1,116,475	210	1,772,336	(656,071)	0
Balance at Dec. 31, 2019	1,083,318	211	1,777,779	(694,672)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock activity and shares exchanged for tax withholding	(635)	1			(636)
Stock-based compensation	1,428		1,428
Retirement of treasury stock	0		(636)		636
Net income (loss)	(1,015,639)			(1,015,639)
Balance at Mar. 31, 2020	$ 68,472	$ 212	$ 1,778,571	$ (1,710,311)	$ 0