Fair Value (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Fair Value
Amortization of premiums on securities included in interest income			$ 49,000	$ 86,000
Credit losses				311,000
Principal amount of impaired commercial and commercial real estate loans	55,400,000		55,400,000		36,400,000
Valuation allowance	16,300,000		16,300,000		13,600,000
Provision for loan losses expensed			10,300,000		7,100,000
Interest and fee income, loans, commercial and residential, real estate	$ 41,000	$ 49,000	$ 141,000	$ 172,000
Past due of mortgage loans held for sale, days	90		90