Derivatives and Hedging Activities (Details 2) (Not Designated as Hedging Instrument [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Gains and losses recognized in income on non-designated hedging instruments
Gains and losses recognized in income on derivatives	$ (662)	$ 598
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	(248)	(1,691)
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	(223)	2,244
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	(191)	45
Other [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