Interest Rate Swap (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Amounts and locations of activity related to the interest rate swaps designated as cash flow hedges within the Corporation's consolidated balance sheet and statement of income
Interest Rate Swaps, Fair Value	$ (1,745)	$ (1,669)
Interest rate swap [Member]
Amounts and locations of activity related to the interest rate swaps designated as cash flow hedges within the Corporation's consolidated balance sheet and statement of income
Interest rate contract	(49)	(522)	(107)
Interest rate swap [Member] | Accrued Interest Payable and Other Liabilities [Member]
Amounts and locations of activity related to the interest rate swaps designated as cash flow hedges within the Corporation's consolidated balance sheet and statement of income
Interest Rate Swaps, Fair Value	(1,745)	(1,669)
Interest rate swap [Member] | Interest Expense Subordinated Debentures [Member]
Amounts and locations of activity related to the interest rate swaps designated as cash flow hedges within the Corporation's consolidated balance sheet and statement of income
Interest expense, Fair Value	(390)	(402)	(401)
Interest rate swap [Member] | Other Income [Member]
Amounts and locations of activity related to the interest rate swaps designated as cash flow hedges within the Corporation's consolidated balance sheet and statement of income
Other income