Guarantees (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Guarantees [Abstract]
Commitments to Extend Credit, Notional Amount	$ 215,498	$ 201,742	$ 198,405
Standby Letters of Credit, Notional Amount	3,562	11,641	10,929
Commitments to Extend Credit, Fair Value	0	0	0
Standby Letters of Credit, Fair Value	$ 52	$ 86	$ 118