Loans, Allowance for Loan Losses, and Credit Quality (Details 9) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2012
Financing Receivable, Modifications [Line Items]
Number of Contracts	59	202
Recorded Investment	$ 14,842	$ 45,865
Unpaid Principal Balance	15,654	51,179
Commercial and Industrial Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	27	82
Recorded Investment	4,984	15,956
Unpaid Principal Balance	5,165	19,053
Commercial Real Estate Owner Occupied Portfolio [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	11	29
Recorded Investment	5,747	11,371
Unpaid Principal Balance	5,958	12,116
Commercial Real Estate Investor Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	3	25
Recorded Investment	3,201	12,514
Unpaid Principal Balance	3,583	13,400
Commercial Real Estate Construction Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	3	8
Recorded Investment	45	864
Unpaid Principal Balance	48	1,214
Home Equity Port Folio Segments [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	9	33
Recorded Investment	619	1,796
Unpaid Principal Balance	652	1,845
Installment [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	5	10
Recorded Investment	138	219
Unpaid Principal Balance	140	222
Residential Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	1	15
Recorded Investment	108	3,145
Unpaid Principal Balance	$ 108	$ 3,329