Loans, Allowance for Loan Losses, and Credit Quality Troubled Debt Restructurings Performing and Nonaccrual (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	$ 117,043	$ 121,087
Nonaccrual Restructured Loans	69,311	80,590
Commercial and Industrial Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	32,145	28,140
Nonaccrual Restructured Loans	12,078	12,496
Commercial Real Estate Owner Occupied Portfolio [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	14,425	13,852
Nonaccrual Restructured Loans	14,004	11,514
Commercial Real Estate Investor Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	35,073	41,660
Nonaccrual Restructured Loans	17,249	25,221
Commercial Real Estate Construction Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	4,825	4,530
Nonaccrual Restructured Loans	4,912	6,798
Home Equity Port Folio Segments [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	9,859	9,968
Nonaccrual Restructured Loans	5,930	6,698
Installment [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	416	653
Nonaccrual Restructured Loans	523	674
Residential Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	20,300	22,284
Nonaccrual Restructured Loans	$ 14,615	$ 17,189