Loans and the Allowance for Loan Losses - (Details 7) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Loan portfolio not subject to risk rating
Loan portfolio	$ 1,948,404	$ 1,551,189
Commercial, financial, agricultural
Loan portfolio not subject to risk rating
Loan portfolio	136,177	115,175
Lease financing
Loan portfolio not subject to risk rating
Loan portfolio	24,279	10,114
Real estate – construction
Loan portfolio not subject to risk rating
Loan portfolio	79,970	60,523
Real estate – 1-4 family mortgage
Loan portfolio not subject to risk rating
Loan portfolio	1,295,599	1,013,375
Real estate – commercial mortgage
Loan portfolio not subject to risk rating
Loan portfolio	301,922	268,219
Installment loans to individuals
Loan portfolio not subject to risk rating
Loan portfolio	110,457	83,783
Performing
Loan portfolio not subject to risk rating
Loan portfolio	1,943,721	1,546,689
Performing | Commercial, financial, agricultural
Loan portfolio not subject to risk rating
Loan portfolio	135,821	114,996
Performing | Lease financing
Loan portfolio not subject to risk rating
Loan portfolio	24,279	10,114
Performing | Real estate – construction
Loan portfolio not subject to risk rating
Loan portfolio	79,970	60,323
Performing | Real estate – 1-4 family mortgage
Loan portfolio not subject to risk rating
Loan portfolio	1,292,638	1,010,645
Performing | Real estate – commercial mortgage
Loan portfolio not subject to risk rating
Loan portfolio	300,582	266,867
Performing | Installment loans to individuals
Loan portfolio not subject to risk rating
Loan portfolio	110,431	83,744
Non- Performing
Loan portfolio not subject to risk rating
Loan portfolio	4,683	4,500
Non- Performing | Commercial, financial, agricultural
Loan portfolio not subject to risk rating
Loan portfolio	356	179
Non- Performing | Lease financing
Loan portfolio not subject to risk rating
Loan portfolio	0	0
Non- Performing | Real estate – construction
Loan portfolio not subject to risk rating
Loan portfolio	0	200
Non- Performing | Real estate – 1-4 family mortgage
Loan portfolio not subject to risk rating
Loan portfolio	2,961	2,730
Non- Performing | Real estate – commercial mortgage
Loan portfolio not subject to risk rating
Loan portfolio	1,340	1,352
Non- Performing | Installment loans to individuals
Loan portfolio not subject to risk rating
Loan portfolio	$ 26	$ 39