Fair Value (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Amortization of premiums on securities included in interest income	$ 72,000	$ 101,000
Credit losses	888,000	930,000
Principal amount of impaired commercial and commercial real estate loans	49,400,000	36,400,000
Valuation allowance	11,300,000	13,600,000
Provision for loan losses expensed	7,500,000	7,100,000
Interest and fee income, loans, commercial and residential, real estate	173,000	214,000
Past due period of mortgage loans held for sale, days	90
States And Political Subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfer in at December 31	1,306,000
Securities transferred to Level 3	$ 1,306,000