Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - 9 months ended Sep. 30, 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	6,857		6,857
Equity issuance costs	(44)		(44)
Issuance of restricted stock		$ 2	(2)
Issuance of restricted stock, shares		153,192
Issuance of common stock upon vesting of equity-based compensation awards, net of shares withheld for income tax withholdings	(2,035)	$ 28	(28)	(2,035)
Issuance of common stock upon vesting of equity-based compensation awards, net of shares withheld for income tax withholdings, shares		1,995,270
Net income	21,647				21,647
Ending Balances at Sep. 30, 2017	$ 583,032	$ 2,637	$ 1,965,514	$ (2,096)	$ (1,383,023)
Ending Balance, shares at Sep. 30, 2017		262,740,355