Loans and Asset Quality Information (Summary of Major Categories of Total Loans Outstanding) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
All loans (non-covered and covered):
Amount of loans	$ 2,480,938	$ 2,395,228	$ 2,425,360
Percentage of Loans	100.00%	100.00%	100.00%
Unamortized net deferred loan costs	$ 765	$ 946	$ 730
Loans, total	2,481,703	2,396,174	2,426,090
Commercial, financial and agricultural [Member]
All loans (non-covered and covered):
Amount of loans	$ 199,630	$ 160,878	$ 165,215
Percentage of Loans	8.00%	7.00%	7.00%
Real Estate construction, land development and other land loans [Member]
All loans (non-covered and covered):
Amount of loans	$ 294,426	$ 288,148	$ 298,091
Percentage of Loans	12.00%	12.00%	13.00%
Real estate mortgage residential (1-4 family) first mortgages [Member]
All loans (non-covered and covered):
Amount of loans	$ 770,691	$ 789,871	$ 806,954
Percentage of Loans	31.00%	33.00%	33.00%
Real estate mortgage home equity loans/lines of credit [Member]
All loans (non-covered and covered):
Amount of loans	$ 224,639	$ 223,500	$ 224,553
Percentage of Loans	9.00%	9.00%	9.00%
Real estate mortgage commercial and other [Member]
All loans (non-covered and covered):
Amount of loans	$ 944,432	$ 882,127	$ 879,122
Percentage of Loans	38.00%	37.00%	36.00%
Installment loans to individual [Member]
All loans (non-covered and covered):
Amount of loans	$ 47,120	$ 50,704	$ 51,425
Percentage of Loans	2.00%	2.00%	2.00%