Income Taxes (Details) (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Current portion of income tax expense:
Federal	$ 0	$ (6,944,000)
State	(393,000)	(175,000)
Deferred portion of income tax expense	(15,288,000)	18,174,000
Total Income tax expense	(15,681,000)	11,055,000
Effective tax rate (as a percent)	37.30%	37.40%
Amount of refund received from net operating loss carryback claim		$ 5,500,000