Derivative Instruments (Details Textual) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 August 2012 [Member] Derivative_Instrument	Sep. 30, 2012 August 2013 [Member] Derivative_Instrument	Sep. 30, 2012 Interest rate swap [Member]	Sep. 30, 2012 Commitments to fund fixed-rate residential mortgage loans [Member]	Dec. 31, 2011 Commitments to fund fixed-rate residential mortgage loans [Member]	Sep. 30, 2012 Commitments to sell residential mortgage loans [Member]	Dec. 31, 2011 Commitments to sell residential mortgage loans [Member]	Sep. 30, 2012 Interest rate contracts with corporate customers [Member]	Sep. 30, 2012 Offsetting interest rate contracts with other financial institutions [Member]
Derivative Instruments (Textual) [Abstract]
Junior subordinated debentures							$ 32,000	$ 80,109	$ 56,217	$ 116,513	$ 42,074	$ 68,913	$ 68,913
Fair value of derivatives							(2,234)
Number of derivative instruments terminated					2	2
Derivative instruments deferred gain	115	154	419	457	1,679	1,679
Derivative Instruments (Additional Textual) [Abstract]
Variable interest rate of derivatives, description			the three-month LIBOR plus pre-determined spread
Notional amount of interest rate cash flow hedge derivatives	$ 75,000		$ 75,000