Loans, Allowance for Loan Losses, and Credit Quality (Details 8) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Financing Receivable Restructuring [Line Items]
Performing Restructured Loans	$ 122,229	$ 113,164
Nonaccrual Restructured Loans	86,395	87,493
Commercial and industrial
Financing Receivable Restructuring [Line Items]
Performing Restructured Loans	28,399	22,552
Nonaccrual Restructured Loans	16,204	12,211
Commercial real estate - owner occupied
Financing Receivable Restructuring [Line Items]
Performing Restructured Loans	7,115	8,138
Nonaccrual Restructured Loans	12,125	9,706
Commercial real estate - investor
Financing Receivable Restructuring [Line Items]
Performing Restructured Loans	49,325	43,417
Nonaccrual Restructured Loans	28,004	30,303
Real estate construction
Financing Receivable Restructuring [Line Items]
Performing Restructured Loans	5,838	10,977
Nonaccrual Restructured Loans	12,782	14,253
Home Equity
Financing Receivable Restructuring [Line Items]
Performing Restructured Loans	9,471	8,950
Nonaccrual Restructured Loans	5,287	6,268
Installment
Financing Receivable Restructuring [Line Items]
Performing Restructured Loans	779	1,015
Nonaccrual Restructured Loans	1,059	1,163
Residential Mortgage
Financing Receivable Restructuring [Line Items]
Performing Restructured Loans	21,302	18,115
Nonaccrual Restructured Loans	$ 10,934	$ 13,589