Fair Values of Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Estimated fair value of impaired loans on nonrecurring basis
Impaired loans, Carrying value	$ 11,637	$ 7,694
Impaired loans, Provision for (Reduction of) Loan Losses	$ 1,163	$ 438