Income Taxes (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Current and Deferred tax expense from continuing operations
Current U.S federal tax expense (benefit)	$ 98,062	$ 151,953	$ 48,532
Current state and local tax expense (benefit)	7,108	14,109	2,790
Current income tax expense (benefit)	105,170	166,062	51,322
Deferred U.S federal tax expense (benefit)	9,641	(2,642)	86
Deferred state and local tax expense (benefit)	(586)	380	732
Deferred income tax expense (benefit)	9,055	(2,262)	818
Federal income tax expense (benefit) from continuing operations	107,703	149,311	48,618
State and local income tax expense (benefit) from continuing operations	6,522	14,489	3,522
Tax benefit recorded by the company	$ 114,225	$ 163,800	$ 52,140