Schedule of Earnings Per Share, Basic and Diluted (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Basic EPS:
Net income (loss)	$ 52,940	$ (602,107)	$ 110,512	$ (546,698)
Weighted average common shares outstanding	50,603,000	50,123,000	50,429,000	50,082,000
Basic (in dollars per share)	$ 1.05	$ (12.01)	$ 2.19	$ (10.92)
Diluted EPS:
Net income (loss)	$ 52,940	$ (602,107)	$ 110,512	$ (546,698)
Weighted average common shares outstanding	50,603,000	50,123,000	50,429,000	50,082,000
Dilutive effect of stock awards (in shares)	0	0	10,000	0
Weighted average diluted shares outstanding	50,603,000	50,123,000	50,439,000	50,082,000
Diluted (in dollars per share)	$ 1.05	$ (12.01)	$ 2.19	$ (10.92)
Stock Compensation Plan
Stock Based Awards Additional Disclosure:
Antidilutive Stock Based Awards Excluded from Computation of Earnings Per Share	3,300,000	3,400,000	2,600,000	3,400,000