Income Taxes (Schedule Of Components Of Income Tax Expense (Benefit)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
U.S. federal, Current	$ 116,753	$ 102,607	$ 110,552
State and local, Current	9,457	6,551	11,637
Current, income tax expense (benefit)	126,210	109,158	122,189
U.S. federal, Deferred	(2,036)	7,084	(679)
State and local, Deferred	(23)	348	139
Deferred, income tax expense (benefit)	(2,059)	7,432	(540)
U.S. federal, Total	114,717	109,691	109,873
State and local, Total	9,434	6,899	11,776
Total income tax expense	$ 124,151	$ 116,590	$ 121,649