Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Numerator [Abstract]
Net income (loss)	$ (770)	$ (3,260)	$ 20,115	$ (91,077)
Denominator [Abstract]
Denominator for basic earnings per share – weighted-average common shares outstanding (shares)	163,508,000	133,546,000	160,031,000	118,274,000
Effect of dilutive securities: Stock options and restricted shares (shares)	0	0	1,566,000	0
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)	163,508,000	133,546,000	161,597,000	118,274,000
Earnings Per Share, Basic [Abstract]
Net income (loss) per common share - basic (in usd per share	$ 0.00	$ (0.02)	$ 0.13	$ (0.77)
Earnings Per Share, Diluted [Abstract]
Net income (loss) per common share - diluted (in usd per share)	$ 0.00	$ (0.02)	$ 0.12	$ (0.77)
Stock options excluded from the calculation of diluted income (loss) per share (in shares)	1,346	1,766	0	1,724