Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator [Abstract]
Net income (loss) from continuing operations									$ (96,378)	$ (127,090)	$ 61,951
Net income (loss) from discontinued operations									0	(20)	1,318
Net income (loss)	$ (5,301)	$ (67,419)	$ (3,260)	$ (46,937)	$ (40,880)	$ (52,372)	$ (6,601)	$ (718)	$ (96,378)	$ (127,110)	$ 63,269
Denominator [Abstract]
Denominator for basic earnings per share – weighted-average common shares outstanding (shares)									122,132,000	104,605,000	98,835,000
Effect of dilutive securities [Abstract]
Stock options, restricted shares and warrants (in shares)									0	0	2,633,000
Dilutive potential common shares [Abstract]
Denominator for diluted earnings per share - adjusted weighted-average shares and assumed exercise of options, restricted shares and warrants (in shares)									122,132,000	104,605,000	101,468,000
Earnings Per Share, Basic [Abstract]
Continuing operations (in dollars per share)									$ (0.79)	$ (1.21)	$ 0.63
Discontinued operations (in dollars per share)									0.00	0.00	0.01
Total (in dollars per share)	$ (0.04)	$ (0.64)	$ (0.02)	$ (0.40)	$ (0.39)	$ (0.50)	$ (0.06)	$ (0.01)	(0.79)	(1.21)	0.64
Earnings Per Share, Diluted [Abstract]
Continuing operations (in dollars per share)									(0.79)	(1.21)	0.61
Discontinued operations (in dollars per share)									0.00	0.00	0.01
Total (in dollars per share)	$ (0.04)	$ (0.64)	$ (0.02)	$ (0.40)	$ (0.39)	$ (0.50)	$ (0.06)	$ (0.01)	$ (0.79)	$ (1.21)	$ 0.62
Stock options excluded from the calculation of diluted income (loss) per share (in shares)									624	0	624