Mortgage Servicing Rights (Schedule Of Changes In Mortgage Servicing Rights) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Mortgage Servicing Rights [Abstract]
Balance, beginning of year	$ 14,454		$ 12,625		$ 8,205
Additions for new mortgage servicing rights capitalized	6,720		5,645		7,570
Acquired mortgage servicing rights			62
Due to changes in model inputs or assumptions	(858)	[1]	(1,598)	[1]	(3,469)	[1]
Other	(2,132)	[2]	(2,280)	[2]	319	[2]
Balance, end of year	18,184		14,454		12,625
Balance of loans serviced for others	$ 2,009,849		$ 1,603,414		$ 1,277,832
MSR as a percentage of serviced loans	0.90%		0.90%		0.99%

[1] Principally reflects changes in discount rates and prepayment speed assumptions, which are primarily affected by changes in interest rates.

[2] Represents changes due to collection/realization of expected cash flows over time.