Income Taxes (Components Of Income Tax Expense) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Taxes [Abstract]
Current, Federal	$ 31,390	$ 23,699	$ 31,676
Deferred, Federal	20,518	9,964	131,839
Federal, Total	51,908	33,663	163,515
Current, State	2,934	(3,225)	1,793
Deferred, State	(907)	(246)	3,161
State, Total	2,027	(3,471)	4,954
Total, Current	34,324	20,474	33,469
Total, Deferred	19,611	9,718	135,000
Total	$ 53,935	$ 30,192	$ 168,469