Loans, Allowance for Loan Losses, and Credit Quality (Details 10) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011
Troubled Debt Restructurings Subsequent Default [Line Items]
Number of Contracts	81
Recorded Investment	$ 20,522
Commercial and industrial
Troubled Debt Restructurings Subsequent Default [Line Items]
Number of Contracts	26
Recorded Investment	2,880
Commercial real estate - owner occupied
Troubled Debt Restructurings Subsequent Default [Line Items]
Number of Contracts	6
Recorded Investment	2,094
Commercial real estate - investor
Troubled Debt Restructurings Subsequent Default [Line Items]
Number of Contracts	16
Recorded Investment	9,546
Real estate construction
Troubled Debt Restructurings Subsequent Default [Line Items]
Number of Contracts	10
Recorded Investment	2,846
Home Equity
Troubled Debt Restructurings Subsequent Default [Line Items]
Number of Contracts	12
Recorded Investment	1,422
Installment
Troubled Debt Restructurings Subsequent Default [Line Items]
Number of Contracts	1
Recorded Investment	20
Residential Mortgage
Troubled Debt Restructurings Subsequent Default [Line Items]
Number of Contracts	10
Recorded Investment	$ 1,714