Derivative Instruments (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Derivatives designated as hedging instruments [Member]
Gains (losses) on derivatives financial instruments included in the Consolidated Statements of Income
Gains (losses) on derivative financial instruments	$ 115	$ 154	$ 419	$ 457
Derivatives not designated as hedging instruments [Member]
Gains (losses) on derivatives financial instruments included in the Consolidated Statements of Income
Gains (losses) on derivative financial instruments	(970)	719	(473)	1,002
Included in interest income on loans [Member] | Derivatives designated as hedging instruments [Member] | Interest rate swaps (terminated May 2010): [Member]
Gains (losses) on derivatives financial instruments included in the Consolidated Statements of Income
Gains (losses) on derivative financial instruments	115	154	419	457
Included in interest income on loans [Member] | Derivatives not designated as hedging instruments [Member] | Interest rate contracts [Member]
Gains (losses) on derivatives financial instruments included in the Consolidated Statements of Income
Gains (losses) on derivative financial instruments	583	203	1,466	363
Included in other noninterest expense [Member] | Derivatives not designated as hedging instruments [Member] | Interest rate contracts [Member]
Gains (losses) on derivatives financial instruments included in the Consolidated Statements of Income
Gains (losses) on derivative financial instruments	(14)		20
Included in gains on sales of mortgage loans held for sale [Member] | Derivatives not designated as hedging instruments [Member] | Interest rate lock commitments [Member]
Gains (losses) on derivatives financial instruments included in the Consolidated Statements of Income
Gains (losses) on derivative financial instruments	1,145	1,324	1,667	1,478
Included in gains on sales of mortgage loans held for sale [Member] | Derivatives not designated as hedging instruments [Member] | Forward commitments [Member]
Gains (losses) on derivatives financial instruments included in the Consolidated Statements of Income
Gains (losses) on derivative financial instruments	$ (2,684)	$ (808)	$ (3,626)	$ (839)