Derivatives and Hedging Activities (Details 2) (Not Designated as Hedging Instrument [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Gains and losses recognized in income on non-designated hedging instruments
Gains and losses recognized in income on derivatives	$ (1,643)	$ 1,531	$ (7,722)
Interest Rate Swap [Member] | Other Expenses [Member]
Gains and losses recognized in income on non-designated hedging instruments
Gains and losses recognized in income on derivatives	0	0	(3,877)
Mortgage loan commitments [Member] | Other income [Member]
Gains and losses recognized in income on non-designated hedging instruments
Gains and losses recognized in income on derivatives	3,576	987	(195)
Forward sales contracts [Member] | Other income [Member]
Gains and losses recognized in income on non-designated hedging instruments
Gains and losses recognized in income on derivatives	(3,904)	1,222	1,401
Dollar Rolls [Member] | Other income [Member]
Gains and losses recognized in income on non-designated hedging instruments
Gains and losses recognized in income on derivatives	0	0	(4,451)
Credit Risk Contract [Member] | Other income [Member]
Gains and losses recognized in income on non-designated hedging instruments
Gains and losses recognized in income on derivatives	9	0	0
Other [Member] | Other Expenses [Member]
Gains and losses recognized in income on non-designated hedging instruments
Gains and losses recognized in income on derivatives	$ (1,324)	$ (678)	$ (600)