Purchased Loans (Details 6) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Loan portfolio not subject to risk rating
Total	$ 6,202,709	$ 5,413,462
Commercial, financial, agricultural
Loan portfolio not subject to risk rating
Total	717,490	636,837
Real estate – construction
Loan portfolio not subject to risk rating
Total	552,679	357,665
Real estate – 1-4 family mortgage
Loan portfolio not subject to risk rating
Total	1,878,177	1,735,323
Real estate – commercial mortgage
Loan portfolio not subject to risk rating
Total	2,898,895	2,533,729
Installment loans to individuals
Loan portfolio not subject to risk rating
Total	155,468	149,908
Purchased
Loan portfolio not subject to risk rating
Total	1,489,137	1,583,028
Purchased | Performing and Non-Performing
Loan portfolio not subject to risk rating
Total	316,127	353,775
Purchased | Performing
Loan portfolio not subject to risk rating
Total	313,852	353,285
Purchased | Non-Performing
Loan portfolio not subject to risk rating
Total	2,275	490
Purchased | Commercial, financial, agricultural
Loan portfolio not subject to risk rating
Total	128,200	151,430
Purchased | Commercial, financial, agricultural | Performing and Non-Performing
Loan portfolio not subject to risk rating
Total	9,568	4,943
Purchased | Commercial, financial, agricultural | Performing
Loan portfolio not subject to risk rating
Total	9,489	4,943
Purchased | Commercial, financial, agricultural | Non-Performing
Loan portfolio not subject to risk rating
Total	79	0
Purchased | Lease financing | Performing and Non-Performing
Loan portfolio not subject to risk rating
Total	0	0
Purchased | Lease financing | Performing
Loan portfolio not subject to risk rating
Total	0	0
Purchased | Lease financing | Non-Performing
Loan portfolio not subject to risk rating
Total	0	0
Purchased | Real estate – construction
Loan portfolio not subject to risk rating
Total	68,753	65,964
Purchased | Real estate – construction | Performing and Non-Performing
Loan portfolio not subject to risk rating
Total	4,067	13,779
Purchased | Real estate – construction | Performing
Loan portfolio not subject to risk rating
Total	3,601	13,779
Purchased | Real estate – construction | Non-Performing
Loan portfolio not subject to risk rating
Total	466	0
Purchased | Real estate – 1-4 family mortgage
Loan portfolio not subject to risk rating
Total	452,447	531,095
Purchased | Real estate – 1-4 family mortgage | Performing and Non-Performing
Loan portfolio not subject to risk rating
Total	267,201	294,708
Purchased | Real estate – 1-4 family mortgage | Performing
Loan portfolio not subject to risk rating
Total	265,697	294,256
Purchased | Real estate – 1-4 family mortgage | Non-Performing
Loan portfolio not subject to risk rating
Total	1,504	452
Purchased | Real estate – commercial mortgage
Loan portfolio not subject to risk rating
Total	823,758	804,680
Purchased | Real estate – commercial mortgage | Performing and Non-Performing
Loan portfolio not subject to risk rating
Total	21,411	13,154
Purchased | Real estate – commercial mortgage | Performing
Loan portfolio not subject to risk rating
Total	21,353	13,154
Purchased | Real estate – commercial mortgage | Non-Performing
Loan portfolio not subject to risk rating
Total	58	0
Purchased | Installment loans to individuals
Loan portfolio not subject to risk rating
Total	15,979	29,859
Purchased | Installment loans to individuals | Performing and Non-Performing
Loan portfolio not subject to risk rating
Total	13,880	27,191
Purchased | Installment loans to individuals | Performing
Loan portfolio not subject to risk rating
Total	13,712	27,153
Purchased | Installment loans to individuals | Non-Performing
Loan portfolio not subject to risk rating
Total	$ 168	$ 38