Mortgage Servicing Rights (Schedule Of Other Information Servicing Loan Portfolio) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2012	Dec. 31, 2011
Mortgage Servicing Rights [Abstract]
Balance of loans serviced for others	$ 2,191,215	$ 2,009,849
MSR as a percentage of serviced loans	0.92%	0.90%