Other Real Estate Owned (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Activity for other real estate owned [Roll Forward]
Beginning balance of other real estate owned	$ 47,537,000	$ 56,965,000
New assets acquired	2,047,000	5,370,000
Capitalized costs	0	90,000
Fair value adjustments	(1,146,000)	(179,000)
Sale of assets	(2,718,000)	(3,092,000)
Ending balance of other real estate owned	45,720,000	59,154,000
Foreclosed properties	45,200,000	58,600,000
Other real estate owned not acquired through foreclosure	500,000
Carrying cost and fair value adjusments for foreclosed properties	$ 1,840,000	$ 790,000	$ 850,000