Net Income (Loss) per Share - Basic and Diluted Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]
Net income (loss) applicable to common shares	$ (24,541)	$ (202,096)	$ 52,626	$ (271,693)
Weighted average number of common shares outstanding	164,149,000	157,143,000	164,021,000	156,842,000
Effect of dilutive stock awards	0	0	305,000	0
Weighted average number of diluted common shares outstanding	164,149,000	157,143,000	164,326,000	156,842,000
Basic net income (loss) per share (in dollars per share)	$ (0.15)	$ (1.29)	$ 0.32	$ (1.73)
Diluted net income (loss) per share (in dollars per share)	$ (0.15)	$ (1.29)	$ 0.32	$ (1.73)