Fair Value (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Fair Value (Textual) [Abstract]
Transfer between level 1 and level 2 due to in the valuation of interest rate caps are back-tested	$ 0	$ 0
Transfer between level 1 and level 2 due to reconciliation of all assets measured at fair value on a recurring basis	0	0
Derivative instrument maximum maturity period	30 years
Fair value of the collateral dependent loans, net carrying amount	9,900,000	54,200,000
Specific allowance for collateral dependent loans	3,000,000	11,800,000
Provision for loan losses	27,000	30,800,000
Discount applied to appraisals for estimated selling costs percentage	10.00%
Other real estate owned carried at fair value	10,100,000	15,200,000
Other real estate owned outstanding amount		23,900,000
Valuation allowance related to other real estate owned	8,000,000	8,800,000
Additional expenses related to other real estate owned	2,200,000	4,700,000
Mortgage servicing rights, fair amount	4,900,000	4,600,000
Mortgage servicing rights outstanding	5,600,000	6,400,000
Valuation allowance	(680,000)	(1,785,000)	(285,000)	(423,000)
Mortgage servicing rights net recovery/charge	1,100,000	1,500,000
Maximum maturity period of short term borrowings	90 days
Minimum [Member]
Fair Value (Additional Textual) [Abstract]
Increase in fair value	$ 250,000