Fair Value Measurement (Details Textual)	6 Months Ended
	Jun. 30, 2012
Fair Value Measurement (Textual) [Abstract]
Maturity days of carrying amounts for cash and due from financial institutions	less than 90
Receiving/ paying days of carrying amounts for accrued interest receivable, accrued interest payable and securities sold under agreements to repurchase	90 days or less
Discount rate is estimated using current rate for mortgage-matched secured borrowing period from FHLB	30 years