Loans, Allowance for Loan Losses, and Credit Quality (Details 9) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
Commercial and industrial
Financing Receivable, Modifications [Line Items]
Number of Contracts	45
Recorded Investment	$ 7,838
Unpaid Principal Balance	8,666
Commercial real estate - owner occupied
Financing Receivable, Modifications [Line Items]
Number of Contracts	9
Recorded Investment	3,496
Unpaid Principal Balance	3,911
Commercial real estate - investor
Financing Receivable, Modifications [Line Items]
Number of Contracts	9
Recorded Investment	2,885
Unpaid Principal Balance	2,898
Real estate construction
Financing Receivable, Modifications [Line Items]
Number of Contracts	4
Recorded Investment	1,485
Unpaid Principal Balance	1,815
Home Equity
Financing Receivable, Modifications [Line Items]
Number of Contracts	13
Recorded Investment	599
Unpaid Principal Balance	604
Installment
Financing Receivable, Modifications [Line Items]
Number of Contracts	4
Recorded Investment	42
Unpaid Principal Balance	42
Residential Mortgage
Financing Receivable, Modifications [Line Items]
Number of Contracts	9
Recorded Investment	2,219
Unpaid Principal Balance	$ 2,291