Derivative Financial Instruments (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
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 loss recognized on derivative	112	394	336	335
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 recognized on derivative	(112)	(394)	(336)	(335)
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 loss recognized on derivative	320		600
Location of gain recognized on derivative		$ 359		$ 1,157