Loans, Allowance for Loan and Lease Losses, and Reserve for Off-Balance Sheet Credit Commitments (Details 6) (USD $)	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Total Troubled Debt Restructured Loans item	Mar. 31, 2012 Total Troubled Debt Restructured Loans item	Mar. 31, 2013 Commercial item	Mar. 31, 2012 Commercial item	Mar. 31, 2012 Fixed item	Mar. 31, 2012 Construction item	Mar. 31, 2013 Home equity loans and lines of credit item
Financing Receivable, Impaired
Troubled debt restructured loans on accrual	$ 49,600,000	$ 48,800,000
TDR loans	81,700,000	94,900,000
Specific Reserves	2,400,000	1,700,000
Number of Contracts			5	7	4	5	1	1	1
Pre-Modification Outstanding Principal			2,072,000	23,169,000	1,727,000	16,982,000	655,000	5,532,000	345,000
Period-End Outstanding Principal			$ 2,049,000	$ 23,090,000	$ 1,704,000	$ 16,903,000	$ 655,000	$ 5,532,000	$ 345,000