Income Taxes (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Current
Federal	$ 80,707,000	$ 12,381,000	$ (1,026,000)
State	31,792,000	(16,425,000)	3,423,000
Total	112,499,000	(4,044,000)	2,397,000
Deferred
Federal	(26,635,000)	20,125,000	(4,841,000)
State	(8,303,000)	9,974,000	558,000
Total	(34,938,000)	30,099,000	(4,283,000)
Income tax expense (benefit)
Federal	54,072,000	32,506,000	(5,867,000)
State	23,489,000	(6,451,000)	3,981,000
Total	77,561,000	26,055,000	(1,886,000)
Income tax benefit from litigation settlement with the California Franchise Tax Board		19,000,000
Expense relating to revisions to correct certain deferred tax accounts		4,300,000
Effective tax provision (benefit) (as a percent)	30.60%	16.20%	(3.80%)
Income taxes receivable	$ 40,300,000	$ 71,100,000