CONSOLIDATED STATEMENTS OF STOCKHOLDERS' DEFICIT - 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, 2014	$ 1,164	$ 1,452,504	$ (87)	$ (1,673,667)	$ (3,263)	$ 0	$ (223,349)
Balance (in shares) at Dec. 31, 2014	116,445				(150)
Increase (Decrease) in Stockholders' Equity
Exercise of stock options, and issuance of common stock units and stock awards	$ 8	(488)	0	0	$ 0	0	(480)
Exercise of stock options, and issuance of common stock units and stock awards (in shares)	740				0
Issuance of common stock in private placement to a related party	$ 4	6,524	0	0	$ 0	0	6,528
Issuance of common stock in private placement to a related party (in shares)	424				0
Stock-based compensation	$ 0	6,873	0	0	$ 0	0	6,873
Repurchase of common stock	$ (27)	(25,609)	0	0	$ 0	0	(25,636)
Repurchase of common stock (in shares)	(2,676)				0
Cash dividends declared, $0.75 per common share	$ 0	(87,906)	0	0	$ 0	0	(87,906)
Net income (loss)	0	0	0	(18,760)	0	0	(18,760)
Other comprehensive income (loss)	0	0	85	0	0	0	85
Balance at Dec. 31, 2015	$ 1,149	1,351,898	(2)	(1,692,427)	$ (3,263)	0	(342,645)
Balance (in shares) at Dec. 31, 2015	114,933				(150)
Increase (Decrease) in Stockholders' Equity
Exercise of stock options, and issuance of common stock units and stock awards	$ 8	(674)	0	0	$ 0	0	(666)
Exercise of stock options, and issuance of common stock units and stock awards (in shares)	853				0
Issuance of common stock in private placement to a related party (in shares)	0				0
Partial termination of capped call options associated with repurchases of convertible notes due 2023	$ 0	578	0	0	$ 0	0	578
Stock-based compensation	0	8,297	0	0	0	0	8,297
Repurchase of common stock	$ (72)	(78,022)	0	0	$ 0	0	(78,094)
Repurchase of common stock (in shares)	(7,201)				0
Net income (loss)	$ 0	0	0	59,536	$ 0	0	59,536
Other comprehensive income (loss)	0	0	3	0	0	0	3
Balance at Dec. 31, 2016	$ 1,085	1,282,077	1	(1,632,891)	$ (3,263)	0	(352,991)
Balance (in shares) at Dec. 31, 2016	108,585				(150)
Increase (Decrease) in Stockholders' Equity
Contributions from noncontrolling interest	$ 0	0	0	0	$ 0	23	23
Exercise of stock options, and issuance of common stock units and stock awards	$ 9	(1,702)	0	0	$ 0	0	(1,693)
Exercise of stock options, and issuance of common stock units and stock awards (in shares)	891				0
Stock-based compensation	$ 0	9,833	0	0	$ 0	0	9,833
Cash dividend forfeited	0	7	0	0	0	0	7
Repurchase of common stock	$ (75)	(97,425)	0	0	$ 0	0	(97,500)
Repurchase of common stock (in shares)	(7,430)				0
Equity components of Convertible Senior Notes due 2025, net of issuance costs	$ 0	65,361	0	0	$ 0	0	65,361
Net income (loss)	0	0	0	134,143	0	129	134,272
Other comprehensive income (loss)	0	0	(19)	0	0	0	(19)
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)