Residential Mortgage Servicing Rights (Schedule Of Information Relates To Serviced Loan Portfolio) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Transfers and Servicing [Abstract]
Balance of loans serviced for others	$ 15,336,597	$ 14,327,368	$ 13,047,266
MSR as a percentage of serviced loans	1.00%	1.00%	1.01%