Residential Mortgage Servicing Rights (Schedule Of Information Relates To Serviced Loan Portfolio) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Transfers and Servicing [Abstract]
Balance of loans serviced for others	$ 15,007,942	$ 14,327,368
MSR as a percentage of serviced loans	0.94%	1.00%