Loans, Allowance for Loan Losses, and Credit Quality (Details 8) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	$ 135,791	$ 113,164
Nonaccrual Restructured Loans	74,251	87,493
Commercial and Industrial Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	35,015	22,552
Nonaccrual Restructured Loans	15,414	12,211
Commercial Real Estate Owner Occupied Portfolio [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	15,706	8,138
Nonaccrual Restructured Loans	11,692	9,706
Commercial Real Estate Investor Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	49,249	43,417
Nonaccrual Restructured Loans	23,985	30,303
Commercial Real Estate Construction Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	3,561	10,977
Nonaccrual Restructured Loans	6,468	14,253
Home Equity Port Folio Segments [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	9,467	8,950
Nonaccrual Restructured Loans	5,477	6,268
Installment [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	672	1,015
Nonaccrual Restructured Loans	1,102	1,163
Residential Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	22,121	18,115
Nonaccrual Restructured Loans	$ 10,113	$ 13,589