Mortgage Servicing Rights (Schedule Of Information Relates To Serviced Loan Portfolio) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Mortgage Servicing Rights [Abstract]
Balance of loans serviced for others	$ 3,162,080	$ 2,009,849	$ 1,603,414
MSR as a percentage of serviced loans	0.87%	0.90%	0.90%