Income Taxes (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Current [Abstract]
Federal	$ (7,188)	$ 37,014	$ 64,389
State	778	10,589	8,284
Foreign	127	4,451	254
Total Current Income Taxes	(6,283)	52,054	72,927
Deferred [Abstract]
Federal	105,528	62,618	(147,607)
State	13,157	4,147	(22,370)
Investment tax credit - net	240	(180)	213
Total Deferred Income Taxes	118,925	66,585	(169,764)
Change in uncertain tax benefits	(1,048)	3,230	562
Change in accrued interest	(1,320)	661	183
Income tax expense benefit	$ 110,274	$ 122,530	$ (96,092)