Loans and Asset Quality Information (Summary of Major Categories of Non-Covered Loans Outstanding) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Non-covered loans:
Total loans	$ 2,374,329	$ 2,267,634	$ 2,292,111
Percentage of Loans	100.00%	100.00%	100.00%
Unamortized net deferred loan costs	$ 765	$ 946	$ 730
Loans - non-covered	2,375,094	2,268,580	2,292,841
Commercial, financial and agricultural [Member]
Non-covered loans:
Total loans	$ 198,624	$ 159,195	$ 162,994
Percentage of Loans	9.00%	7.00%	7.00%
Real Estate construction, land development and other land loans [Member]
Non-covered loans:
Total loans	$ 290,465	$ 282,604	$ 292,401
Percentage of Loans	12.00%	13.00%	13.00%
Real estate mortgage residential (1-4 family) first mortgages [Member]
Non-covered loans:
Total loans	$ 692,431	$ 700,101	$ 714,879
Percentage of Loans	29.00%	31.00%	31.00%
Real estate mortgage home equity loans/lines of credit [Member]
Non-covered loans:
Total loans	$ 213,435	$ 210,697	$ 211,477
Percentage of Loans	9.00%	9.00%	9.00%
Real estate mortgage commercial and other [Member]
Non-covered loans:
Total loans	$ 932,254	$ 864,333	$ 858,935
Percentage of Loans	39.00%	38.00%	38.00%
Installment loans to individual [Member]
Non-covered loans:
Total loans	$ 47,120	$ 50,704	$ 51,425
Percentage of Loans	2.00%	2.00%	2.00%