Loans and Asset Quality Information (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
All loans (non-covered and covered):
Amount of loans	$ 2,394,828	$ 2,375,133	$ 2,435,284
Percentage of Loans	100.00%	100.00%	100.00%
Unamortized net deferred loan costs	1,323	1,324	1,340
Loans, total	2,396,151	2,376,457	2,436,624
Commercial, financial and agricultural
All loans (non-covered and covered):
Amount of loans	162,074	160,790	159,496
Percentage of Loans	7.00%	7.00%	7.00%
Real Estate construction, land development and other land loans
All loans (non-covered and covered):
Amount of loans	293,918	298,458	355,709
Percentage of Loans	12.00%	13.00%	15.00%
Real estate mortgage residential (1-4 family) first mortgages
All loans (non-covered and covered):
Amount of loans	831,467	815,281	812,878
Percentage of Loans	35.00%	34.00%	33.00%
Real estate mortgage home equity loans/lines of credit
All loans (non-covered and covered):
Amount of loans	236,222	238,925	255,955
Percentage of Loans	10.00%	10.00%	10.00%
Real estate mortgage commercial and other
All loans (non-covered and covered):
Amount of loans	803,875	789,746	775,610
Percentage of Loans	33.00%	33.00%	32.00%
Installment loans to individual
All loans (non-covered and covered):
Amount of loans	$ 67,272	$ 71,933	$ 75,636
Percentage of Loans	3.00%	3.00%	3.00%