Loans and the Allowance for Loan Losses - (Details 7) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Loan portfolio not subject to risk rating
Total	$ 2,101,447	$ 2,011,292
Commercial, financial, agricultural
Loan portfolio not subject to risk rating
Total	165,272	144,931
Lease financing
Loan portfolio not subject to risk rating
Total	41,937	34,815
Real estate – construction
Loan portfolio not subject to risk rating
Total	85,222	81,035
Real estate – 1-4 family mortgage
Loan portfolio not subject to risk rating
Total	1,381,098	1,343,233
Real estate – commercial mortgage
Loan portfolio not subject to risk rating
Total	317,331	294,909
Installment loans to individuals
Loan portfolio not subject to risk rating
Total	110,587	112,369
Performing
Loan portfolio not subject to risk rating
Total	2,096,366	2,007,361
Performing | Commercial, financial, agricultural
Loan portfolio not subject to risk rating
Total	165,137	144,838
Performing | Lease financing
Loan portfolio not subject to risk rating
Total	41,937	34,815
Performing | Real estate – construction
Loan portfolio not subject to risk rating
Total	85,153	81,035
Performing | Real estate – 1-4 family mortgage
Loan portfolio not subject to risk rating
Total	1,377,078	1,340,356
Performing | Real estate – commercial mortgage
Loan portfolio not subject to risk rating
Total	316,594	294,042
Performing | Installment loans to individuals
Loan portfolio not subject to risk rating
Total	110,467	112,275
Non- Performing
Loan portfolio not subject to risk rating
Total	5,081	3,931
Non- Performing | Commercial, financial, agricultural
Loan portfolio not subject to risk rating
Total	135	93
Non- Performing | Lease financing
Loan portfolio not subject to risk rating
Total	0	0
Non- Performing | Real estate – construction
Loan portfolio not subject to risk rating
Total	69	0
Non- Performing | Real estate – 1-4 family mortgage
Loan portfolio not subject to risk rating
Total	4,020	2,877
Non- Performing | Real estate – commercial mortgage
Loan portfolio not subject to risk rating
Total	737	867
Non- Performing | Installment loans to individuals
Loan portfolio not subject to risk rating
Total	$ 120	$ 94