Non Purchased Loans (Details 1) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Past due and nonaccrual loans
Total loans, gross	$ 6,205,118	$ 5,414,625
Unearned income	(2,409)	(1,163)
Loans, net of unearned income	6,202,709	5,413,462
Commercial, financial, agricultural
Past due and nonaccrual loans
Total loans, gross	717,490	636,837
Loans, net of unearned income	717,490	636,837
Lease financing
Past due and nonaccrual loans
Total loans, gross	49,250	35,978
Real estate – construction
Past due and nonaccrual loans
Total loans, gross	552,679	357,665
Loans, net of unearned income	552,679	357,665
Real estate – 1-4 family mortgage
Past due and nonaccrual loans
Total loans, gross	1,878,177	1,735,323
Loans, net of unearned income	1,878,177	1,735,323
Real estate – commercial mortgage
Past due and nonaccrual loans
Total loans, gross	2,898,895	2,533,729
Loans, net of unearned income	2,898,895	2,533,729
Installment loans to individuals
Past due and nonaccrual loans
Total loans, gross	108,627	115,093
Loans, net of unearned income	155,468	149,908
Non-Purchased
Past due and nonaccrual loans
Total loans, gross	4,715,981	3,831,597
Unearned income	(2,409)	(1,163)
Loans, net of unearned income	4,713,572	3,830,434
Non-Purchased | Accruing Loans
Past due and nonaccrual loans
Current Loans	4,689,425	3,808,201
Unearned income	(2,409)	(1,163)
Loans, net of unearned income	4,702,299	3,816,790
Non-Purchased | Accruing Loans | 30-89 Days Past Due
Past due and nonaccrual loans
Loans past due	10,795	7,263
Non-Purchased | Accruing Loans | 90 Days or More Past Due
Past due and nonaccrual loans
Loans past due	2,079	1,326
Non-Purchased | Nonaccruing Loans
Past due and nonaccrual loans
Current Loans	5,441	9,083
Unearned income	0	0
Loans, net of unearned income	11,273	13,644
Non-Purchased | Nonaccruing Loans | 30-89 Days Past Due
Past due and nonaccrual loans
Loans past due	741	968
Non-Purchased | Nonaccruing Loans | 90 Days or More Past Due
Past due and nonaccrual loans
Loans past due	5,091	3,593
Non-Purchased | Commercial, financial, agricultural
Past due and nonaccrual loans
Total loans, gross	589,290	485,407
Non-Purchased | Commercial, financial, agricultural | Accruing Loans
Past due and nonaccrual loans
Current Loans	586,730	485,095
Total loans, gross	588,261	485,309
Non-Purchased | Commercial, financial, agricultural | Accruing Loans | 30-89 Days Past Due
Past due and nonaccrual loans
Loans past due	811	176
Non-Purchased | Commercial, financial, agricultural | Accruing Loans | 90 Days or More Past Due
Past due and nonaccrual loans
Loans past due	720	38
Non-Purchased | Commercial, financial, agricultural | Nonaccruing Loans
Past due and nonaccrual loans
Current Loans	97	0
Total loans, gross	1,029	98
Non-Purchased | Commercial, financial, agricultural | Nonaccruing Loans | 30-89 Days Past Due
Past due and nonaccrual loans
Loans past due	0	30
Non-Purchased | Commercial, financial, agricultural | Nonaccruing Loans | 90 Days or More Past Due
Past due and nonaccrual loans
Loans past due	932	68
Non-Purchased | Lease financing
Past due and nonaccrual loans
Total loans, gross	49,250	35,978
Non-Purchased | Lease financing | Accruing Loans
Past due and nonaccrual loans
Current Loans	48,919	35,978
Total loans, gross	49,112	35,978
Non-Purchased | Lease financing | Accruing Loans | 30-89 Days Past Due
Past due and nonaccrual loans
Loans past due	193	0
Non-Purchased | Lease financing | Accruing Loans | 90 Days or More Past Due
Past due and nonaccrual loans
Loans past due	0	0
Non-Purchased | Lease financing | Nonaccruing Loans
Past due and nonaccrual loans
Current Loans	0	0
Total loans, gross	138	0
Non-Purchased | Lease financing | Nonaccruing Loans | 30-89 Days Past Due
Past due and nonaccrual loans
Loans past due	0	0
Non-Purchased | Lease financing | Nonaccruing Loans | 90 Days or More Past Due
Past due and nonaccrual loans
Loans past due	138	0
Non-Purchased | Real estate – construction
Past due and nonaccrual loans
Total loans, gross	483,926	291,701
Non-Purchased | Real estate – construction | Accruing Loans
Past due and nonaccrual loans
Current Loans	482,931	291,633
Total loans, gross	483,926	291,701
Non-Purchased | Real estate – construction | Accruing Loans | 30-89 Days Past Due
Past due and nonaccrual loans
Loans past due	995	68
Non-Purchased | Real estate – construction | Accruing Loans | 90 Days or More Past Due
Past due and nonaccrual loans
Loans past due	0	0
Non-Purchased | Real estate – construction | Nonaccruing Loans
Past due and nonaccrual loans
Current Loans	0	0
Total loans, gross	0	0
Non-Purchased | Real estate – construction | Nonaccruing Loans | 30-89 Days Past Due
Past due and nonaccrual loans
Loans past due	0	0
Non-Purchased | Real estate – construction | Nonaccruing Loans | 90 Days or More Past Due
Past due and nonaccrual loans
Loans past due	0	0
Non-Purchased | Real estate – 1-4 family mortgage
Past due and nonaccrual loans
Total loans, gross	1,425,730	1,204,228
Non-Purchased | Real estate – 1-4 family mortgage | Accruing Loans
Past due and nonaccrual loans
Current Loans	1,414,254	1,192,318
Total loans, gross	1,421,579	1,197,586
Non-Purchased | Real estate – 1-4 family mortgage | Accruing Loans | 30-89 Days Past Due
Past due and nonaccrual loans
Loans past due	6,189	4,461
Non-Purchased | Real estate – 1-4 family mortgage | Accruing Loans | 90 Days or More Past Due
Past due and nonaccrual loans
Loans past due	1,136	807
Non-Purchased | Real estate – 1-4 family mortgage | Nonaccruing Loans
Past due and nonaccrual loans
Current Loans	2,768	4,415
Total loans, gross	4,151	6,642
Non-Purchased | Real estate – 1-4 family mortgage | Nonaccruing Loans | 30-89 Days Past Due
Past due and nonaccrual loans
Loans past due	161	370
Non-Purchased | Real estate – 1-4 family mortgage | Nonaccruing Loans | 90 Days or More Past Due
Past due and nonaccrual loans
Loans past due	1,222	1,857
Non-Purchased | Real estate – commercial mortgage
Past due and nonaccrual loans
Total loans, gross	2,075,137	1,729,049
Non-Purchased | Real estate – commercial mortgage | Accruing Loans
Past due and nonaccrual loans
Current Loans	2,066,821	1,719,329
Total loans, gross	2,069,203	1,722,145
Non-Purchased | Real estate – commercial mortgage | Accruing Loans | 30-89 Days Past Due
Past due and nonaccrual loans
Loans past due	2,283	2,391
Non-Purchased | Real estate – commercial mortgage | Accruing Loans | 90 Days or More Past Due
Past due and nonaccrual loans
Loans past due	99	425
Non-Purchased | Real estate – commercial mortgage | Nonaccruing Loans
Past due and nonaccrual loans
Current Loans	2,576	4,668
Total loans, gross	5,934	6,904
Non-Purchased | Real estate – commercial mortgage | Nonaccruing Loans | 30-89 Days Past Due
Past due and nonaccrual loans
Loans past due	580	568
Non-Purchased | Real estate – commercial mortgage | Nonaccruing Loans | 90 Days or More Past Due
Past due and nonaccrual loans
Loans past due	2,778	1,668
Non-Purchased | Installment loans to individuals
Past due and nonaccrual loans
Total loans, gross	92,648	85,234
Non-Purchased | Installment loans to individuals | Accruing Loans
Past due and nonaccrual loans
Current Loans	92,179	85,011
Total loans, gross	92,627	85,234
Non-Purchased | Installment loans to individuals | Accruing Loans | 30-89 Days Past Due
Past due and nonaccrual loans
Loans past due	324	167
Non-Purchased | Installment loans to individuals | Accruing Loans | 90 Days or More Past Due
Past due and nonaccrual loans
Loans past due	124	56
Non-Purchased | Installment loans to individuals | Nonaccruing Loans
Past due and nonaccrual loans
Current Loans	0	0
Total loans, gross	21	0
Non-Purchased | Installment loans to individuals | Nonaccruing Loans | 30-89 Days Past Due
Past due and nonaccrual loans
Loans past due	0	0
Non-Purchased | Installment loans to individuals | Nonaccruing Loans | 90 Days or More Past Due
Past due and nonaccrual loans
Loans past due	$ 21	$ 0