Loans and Allowance for Loan Losses (Details 9) (USD $) In Thousands, unless otherwise specified				3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Mar. 31, 2013 Purchased Impaired [Member]	Mar. 31, 2012 Purchased Impaired [Member]	Mar. 31, 2013 Purchased Nonimpaired [Member]	Mar. 31, 2012 Purchased Nonimpaired [Member]
Accretable Yield
Balance at beginning of period				$ 3,147	$ 5,140	$ 5,350	$ 9,010
Accretion					(18)	(579)	(1,256)
Charge-offs				(11)	(3)
Transfers to OREO
Payment received, net
Balance at end of period				3,136	5,119	4,771	7,754
Carrying Amount of Loans
Balance at beginning of period	4,019	4,565	8,140	4,565	9,897	473,283	663,510
Accretion
Charge-offs				(96)	(3)	(380)	(541)
Transfers to OREO				(201)	(1,713)	(207)	(2,766)
Payments received, net				(249)	(41)	(27,818)	(88,665)
Balance at end of period	$ 4,019	$ 4,565	$ 8,140	$ 4,019	$ 8,140	$ 444,878	$ 571,538