Income Taxes (Schedule Of Income Tax Expense Attributable To Operations) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Taxes [Abstract]
Current, Federal	$ 44,994	$ 58,853	$ 44,923
Current, State	5,091	6,617	4,623
Current, Foreign	14	0	0
Total current	50,099	65,470	49,546
Deferred, Federal	56,772	46,190	35,046
Deferred, State	6,211	5,259	2,699
Deferred, Foreign	0	0	0
Total deferred	62,983	51,449	37,745
Total income tax expense	113,082	116,919	87,291
Stockholders' equity, for compensation expense for tax purposes in excess of amounts recognized for financial reporting purposes	(415)	(1,419)	(4,448)
Total income tax expense allocation	$ 112,667	$ 115,500	$ 82,843