CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Treasury Stock	Noncontrolling Interest	Total
Balance at Dec. 31, 2017	$ 1,019	$ 1,258,151	$ (18)	$ (1,498,748)	$ (3,263)	$ 152	$ (242,707)
Balance (in shares) at Dec. 31, 2017	102,046				(150)
Increase (Decrease) in Stockholders' Equity
Distributions to noncontrolling interest	$ 0	0	0	0	$ 0	(5,955)	(5,955)
Exercise of stock options, and issuance of common stock units and stock awards, net of repurchase of shares to satisfy tax withholding	$ (8)	(1,926)	0	0	0	0	(1,934)
Exercise of stock options, and issuance of common stock units and stock awards, net of repurchase of shares to satisfy tax withholding (in shares)	(798)
Stock-based compensation	$ 0	3,233	0	0	0	0	3,233
Cash dividend forfeited	0	72	0	0	0	0	72
Retirement of treasury stock	$ 0	(3,263)	0	0	$ 3,263	0	0
Retirement of treasury stock (in shares)	(150)				150
Net income	$ 0	0	0	395,056	$ 0	11,272	406,328
Other comprehensive income	0	0	15	0	0	0	15
Balance at Dec. 31, 2018	$ 1,011	1,256,267	(3)	(1,103,692)	0	5,469	159,052
Balance (in shares) at Dec. 31, 2018	101,098
Increase (Decrease) in Stockholders' Equity
Distributions to noncontrolling interest	$ 0	0	0	0	0	(10,553)	(10,553)
Exercise of stock options, and issuance of common stock units and stock awards, net of repurchase of shares to satisfy tax withholding	$ 2	536	0	0	0	0	538
Exercise of stock options, and issuance of common stock units and stock awards, net of repurchase of shares to satisfy tax withholding (in shares)	190
Stock-based compensation	$ 0	2,056	0	0	0	0	2,056
Net income	0	0	0	157,288	0	33,705	190,993
Other comprehensive income	0	0	30	0	0	0	30
Balance at Dec. 31, 2019	$ 1,013	1,258,859	27	(946,404)	0	28,621	$ 342,116
Balance (in shares) at Dec. 31, 2019	101,288						101,288
Increase (Decrease) in Stockholders' Equity
Distributions to noncontrolling interest	$ 0	0	0	0	0	(30,474)	$ (30,474)
Equity activity of noncontrolling interest from a consolidated variable interest entity	0	0	0	0	0	366	366
Exercise of stock options, and issuance of common stock units and stock awards, net of repurchase of shares to satisfy tax withholding	$ 1	343	0	0	0	0	344
Exercise of stock options, and issuance of common stock units and stock awards, net of repurchase of shares to satisfy tax withholding (in shares)	104
Stock-based compensation	$ 0	1,698	0	0	0	0	1,698
Net income	0	0	0	224,402	0	69,412	293,814
Other comprehensive income	0	0	(27)	0	0	0	(27)
Balance at Dec. 31, 2020	$ 1,014	$ 1,260,900	$ 0	$ (722,002)	$ 0	$ 67,925	$ 607,837
Balance (in shares) at Dec. 31, 2020	101,392						101,392