Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - 3 months ended Mar. 31, 2017 - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Deficit [Member]
Beginning Balances at Dec. 31, 2016	$ 556,607	$ 2,607	$ 1,958,731	$ (61)	$ (1,404,670)
Beginning Balance, shares at Dec. 31, 2016		260,591,893
Stock-based compensation	2,081		2,081
Issuance of common stock upon vesting of equity-based compensation awards, net of shares withheld for income tax withholdings	(1,706)	$ 24	(24)	(1,706)
Issuance of common stock upon vesting of equity-based compensation awards, net of shares withheld for income tax withholdings, shares		1,648,085
Net income	26,847				26,847
Ending Balances at Mar. 31, 2017	$ 583,829	$ 2,631	$ 1,960,788	$ (1,767)	$ (1,377,823)
Ending Balance, shares at Mar. 31, 2017		262,239,978