Commitments and Contingent Liabilities - Financial instruments whose contract amount represents credit risk (Details) (Credit Risk, USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Commitments to extend credit
Commitments and Contingent Liabilities [Line Items]
Contractual amount of financial instruments	$ 44,462	$ 42,173
Standby letters of credit
Commitments and Contingent Liabilities [Line Items]
Contractual amount of financial instruments	$ 673	$ 637