Income Taxes (Schedule Of Components Of Income Tax Expense (Benefit)) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Taxes [Abstract]
U.S. federal, Current	$ 113,920	$ 98,592	$ 77,753
State and local, Current	10,328	6,742	3,314
U.S. federal, Deferred	(2,720)	(6,612)	(6,719)
State and local, Deferred	(116)	(2,473)	(591)
U.S. federal, Total	111,200	91,980	71,034
State and local, Total	10,212	4,269	2,723
Current, income tax expense (benefit)	124,248	105,334	81,067
Deferred, income tax expense (benefit)	(2,836)	(9,085)	(7,310)
Income tax expense (benefit)	$ 121,412	$ 96,249	$ 73,757