Other borrowings (Details Textual) (USD $)	0 Months Ended	1 Months Ended	12 Months Ended
	Sep. 15, 2012	Aug. 31, 2009	Dec. 31, 2012	Dec. 31, 2011
Other Borrowings (Textual) [Abstract]
Subordinated debentures due Date			Sep. 15, 2037
Deferment of interest and dividend payment permitted consecutive period without resulting default		5 years
Other Borrowings (Additional Textual) [Abstract]
Trust preferred securities, issuance, value			$ 5,000,000
Subordinated debentures, fixed interest rate	6.648%
Trust Preferred Securities			5,000,000
Accrued Interest			1,400,000
Trust Preferred Securities due year			2037
Interest accrued related to deferred interest due year			2014
Dividends deferred period			2009-04
Subordinated debentures, variable interest rate description			Interest rate becomes variable at 133 basis points over the three month LIBOR rate
Subordinated debentures, basis spread on LIBOR rate			1.33%
Subordinated debentures, effective interest rate			1.72%
Obligations for securities sold under agreements			5,900,000	11,700,000
Repurchase agreement, securities pledged as collateral, amortized cost			10,000,000	11,600,000
Repurchase agreement, securities pledged as collateral, fair value			10,000,000	13,700,000
Repurchase agreement average month end balance			7,400,000	7,900,000
Maximum [Member]
Other Borrowings (Textual) [Abstract]
Repurchase Agreement Any Month End Balance			$ 9,700,000	$ 11,700,000
Deferment of interest and dividend payment permitted consecutive period without resulting default			5 years