Commitments and Contingent Liabilities (Commitments to Extend Credit) (Details) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Long-term Credit Commitments [Line Items]
Residential mortgage loans, repurchase obligation amount	$ 2,600,000	$ 613,000
Reserve for Off-balance Sheet Activities
Long-term Credit Commitments [Line Items]
Reserve for unfunded commitments	98,000	127,000
Commitments to Extend Credit
Long-term Credit Commitments [Line Items]
Commitments to extend credit, amount	844,600,000	765,800,000
Standby Letters of Credit
Long-term Credit Commitments [Line Items]
Commitments to extend credit, amount	$ 29,500,000	$ 49,100,000