Loans (Details 5) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Nonaccrual loans and loans past due over 90 days still accruing interest by class of loans
Nonaccrual	$ 14,445	$ 16,567
Past Due Over 90 Days Still on Accrual	357	441
Commercial, industrial, and agricultural [Member]
Nonaccrual loans and loans past due over 90 days still accruing interest by class of loans
Nonaccrual	3,073	6,949
Past Due Over 90 Days Still on Accrual		10
Commercial mortgages [Member]
Nonaccrual loans and loans past due over 90 days still accruing interest by class of loans
Nonaccrual	8,570	8,359
Past Due Over 90 Days Still on Accrual	109	122
Residential real estate [Member]
Nonaccrual loans and loans past due over 90 days still accruing interest by class of loans
Nonaccrual	2,792	1,254
Past Due Over 90 Days Still on Accrual	18	157
Consumer [Member]
Nonaccrual loans and loans past due over 90 days still accruing interest by class of loans
Nonaccrual	10	5
Past Due Over 90 Days Still on Accrual	217	125
Credit cards [Member]
Nonaccrual loans and loans past due over 90 days still accruing interest by class of loans
Nonaccrual
Past Due Over 90 Days Still on Accrual	$ 13	$ 27