Derivative Instruments (Details Textual) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Derivative Instruments (Textual) [Abstract]
Variable interest rate of derivatives, description			the three-month LIBOR plus a pre-determined spread
Notional amount of interest rate cash flow hedge derivatives	$ 75,000		$ 75,000
August 2012 [Member]
Derivative Instruments (Textual) [Abstract]
Number of derivative instruments terminated (derivative instruments)			2
Derivative instruments deferred gain			1,679
Designated as hedging instruments [Member]
Derivative Instruments (Textual) [Abstract]
Derivative Liabilities	232		232		2,164
Deferred gains amortized into net interest income	80	152	165	304
August Two Thousand and Twelve [Member]
Derivative Instruments (Textual) [Abstract]
Number of derivative instruments terminated (derivative instruments)			2
Derivative instruments deferred gain			1,679
Interest rate contracts with corporate customers [Member]
Derivative Instruments (Textual) [Abstract]
Junior subordinated debentures	80,408		80,408
Offsetting interest rate contracts with other financial institutions [Member]
Derivative Instruments (Textual) [Abstract]
Junior subordinated debentures	80,408		80,408
Interest rate swaps [Member]
Derivative Instruments (Textual) [Abstract]
Junior subordinated debentures	32,000		32,000
Commitments to fund fixed-rate residential mortgage loans [Member]
Derivative Instruments (Textual) [Abstract]
Junior subordinated debentures	112,070		112,070		72,757
Commitments to sell residential mortgage loans [Member]
Derivative Instruments (Textual) [Abstract]
Junior subordinated debentures	$ 167,000		$ 167,000		$ 100,000