Earnings Per Common Share (Reconciliation of Earnings (loss) Per Common Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Numerator (both basic and diluted)
Net income (loss)	$ (29,991)	$ (77,281)	$ (57,690)	$ (89,300)
Denominator
Weighted-average shares (denominator for basic earnings per share)	64,781	64,342	64,679	64,168
Diluted effect of outstanding stock options, restricted stock and restricted stock unit awards	0	0	0	0
Denominator for diluted earnings per share	64,781	64,342	64,679	64,168
Income (loss) per common share - Basic	$ (0.46)	$ (1.20)	$ (0.89)	$ (1.39)
Income (loss) per common share - Diluted	$ (0.46)	$ (1.20)	$ (0.89)	$ (1.39)
Stock Compensation Plan [Member]
Denominator
Potentially dilutive securities excluded as anti-dilutive	5,095	4,718	5,152	4,894