Loans (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Composition of nonaccrual loans and impaired loans
Loans on nonaccrual	$ 4,471	$ 5,827	$ 8,068
Loans 90 days past due and still accruing		18	50
Impaired loans on nonaccrual included above	2,878	3,468	5,353
Total recorded investment in impaired loans	5,925	8,102	7,963
Average recorded investment of impaired loans	7,043	10,284	9,606
Accruing troubled debt restructures	3,048	4,634	1,248
Interest income not recorded on nonaccrual loans according to their original terms	753	846	1,313
Interest income on nonaccrual loan actually recorded
Interest income recognized on impaired loans	$ 180	$ 155	$ 256