Derivative Financial Instruments (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Derivative in fair value hedging relationship [Member]
Effect of the derivative instruments on the consolidated statement of income Derivative in fair value hedging relationship
Location of gain (loss) recognized on derivative
Interest Rate Contracts One [Member] | Derivative in fair value hedging relationship [Member] | Interest Income [Member]
Effect of the derivative instruments on the consolidated statement of income Derivative in fair value hedging relationship
Location of gain (loss) recognized on derivative	28	147	898
Interest Rate Contracts Two [Member] | Derivative in fair value hedging relationship [Member] | Interest Income [Member]
Effect of the derivative instruments on the consolidated statement of income Derivative in fair value hedging relationship
Location of gain (loss) recognized on derivative	(28)	(147)	(898)
Derivatives not designated as hedging instruments [Member] | Mortgage contracts [Member] | Other income - gain on sale of loans [Member]
Effect of the derivative instruments on the consolidated statement of income Derivative in fair value hedging relationship
Location of gain (loss) recognized on derivative	$ 196	$ 255	$ (538)