Income Taxes (Schedule Of Company's Actual Income Tax Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Computed “expected” tax expense	$ 139,840	$ 133,112	$ 134,191
Tax-exempt interest, net of cost to carry	(20,033)	(19,083)	(17,806)
State and local income taxes, net of federal tax benefit	6,132	4,484	7,655
Tax deductible dividends on allocated shares held by the Company’s ESOP	(1,044)	(1,093)	(1,116)
Other	(744)	(830)	(1,275)
Total income tax expense	$ 124,151	$ 116,590	$ 121,649