Loans, Allowance for Loan Losses, and Credit Quality (Details 8) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	$ 120,093	$ 121,087
Nonaccrual Restructured Loans	67,811	80,590
Commercial and Industrial Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	29,251	28,140
Nonaccrual Restructured Loans	9,221	12,496
Commercial Real Estate Owner Occupied Portfolio [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	12,888	13,852
Nonaccrual Restructured Loans	10,407	11,514
Commercial Real Estate Investor Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	41,253	41,660
Nonaccrual Restructured Loans	20,446	25,221
Commercial Real Estate Construction Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	5,540	4,530
Nonaccrual Restructured Loans	5,494	6,798
Home Equity Port Folio Segments [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	9,556	9,968
Nonaccrual Restructured Loans	7,207	6,698
Installment [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	664	653
Nonaccrual Restructured Loans	665	674
Residential Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	20,941	22,284
Nonaccrual Restructured Loans	$ 14,371	$ 17,189