Securities (Carrying Value of Securities Pledged as Collateral) (Details) (USD $) In Thousands	Jun. 30, 2011
Carrying amount of securities pledged as collateral	$ 406,936
Washington and Oregon State Public Deposits [Member]
Carrying amount of securities pledged as collateral	220,540
Federal Reserve Bank Borrowings [Member]
Carrying amount of securities pledged as collateral	51,657
Federal Home Loan Bank Advances [Member]
Carrying amount of securities pledged as collateral	92,418
Repurchase Agreement [Member]
Carrying amount of securities pledged as collateral	27,556
Interest Rate Contracts [Member]
Carrying amount of securities pledged as collateral	13,336
Other [Member]
Carrying amount of securities pledged as collateral	$ 1,429