Derivative Instruments and Hedging Activities - Income Statement Items for Derivatives not Designated as Hedging Instruments (Details 2) (Not designated as hedging instruments [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Income for derivatives not designated as hedging instruments [Abstract]
Income for derivatives not designated as hedging instruments	$ 242	$ 145	$ 837	$ (468)
Net gain (loss) on mortgage banking activities [Member] | Interest rate locks with customers [Member]
Income for derivatives not designated as hedging instruments [Abstract]
Income for derivatives not designated as hedging instruments	725	109	947	(231)
Net gain (loss) on mortgage banking activities [Member] | Forward loan commitments [Member]
Income for derivatives not designated as hedging instruments [Abstract]
Income for derivatives not designated as hedging instruments	$ (483)	$ 36	$ (110)	$ (237)