Loans, Allowance for Loan Losses, and Credit Quality (Details 8) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	$ 121,087	$ 113,164
Nonaccrual Restructured Loans	80,590	87,493
Commercial and Industrial Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	28,140	22,552
Nonaccrual Restructured Loans	12,496	12,211
Commercial Real Estate Owner Occupied Portfolio [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	13,852	8,138
Nonaccrual Restructured Loans	11,514	9,706
Commercial Real Estate Investor Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	41,660	43,417
Nonaccrual Restructured Loans	25,221	30,303
Commercial Real Estate Construction Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	4,530	10,977
Nonaccrual Restructured Loans	6,798	14,253
Home Equity Portfolio Segments [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	9,968	8,950
Nonaccrual Restructured Loans	6,698	6,268
Installment [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	653	1,015
Nonaccrual Restructured Loans	674	1,163
Residential Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	22,284	18,115
Nonaccrual Restructured Loans	$ 17,189	$ 13,589