Non Purchased Loans - Aging of Past Due and Nonaccrual Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Past due and nonaccrual loans
Loans, net of unearned income	$ 11,000,796	$ 9,693,463
Commercial, financial, agricultural
Past due and nonaccrual loans
Loans, net of unearned income	2,641,598	1,367,972
Lease financing
Past due and nonaccrual loans
Loans, net of unearned income	84,271	85,700
Real estate – construction:
Past due and nonaccrual loans
Loans, net of unearned income	791,108	826,483
Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Loans, net of unearned income	2,788,513	2,866,613
Real estate – commercial mortgage:
Past due and nonaccrual loans
Loans, net of unearned income	4,410,753	4,244,265
Installment loans to individuals
Past due and nonaccrual loans
Loans, net of unearned income	284,553	302,430
Residential | Real estate – construction:
Past due and nonaccrual loans
Loans, net of unearned income	295,931	289,050
Commercial | Real estate – construction:
Past due and nonaccrual loans
Loans, net of unearned income	495,177	537,433
Primary | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Loans, net of unearned income	1,756,253	1,781,948
Home equity | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Loans, net of unearned income	543,468	573,540
Rental/investment | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Loans, net of unearned income	318,803	335,100
Land development | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Loans, net of unearned income	169,989	176,025
Land development | Real estate – commercial mortgage:
Past due and nonaccrual loans
Loans, net of unearned income	155,766	156,089
Owner-occupied | Real estate – commercial mortgage:
Past due and nonaccrual loans
Loans, net of unearned income	1,660,674	1,637,281
Non-owner occupied | Real estate – commercial mortgage:
Past due and nonaccrual loans
Loans, net of unearned income	2,594,313	2,450,895
Non purchased loans and leases
Past due and nonaccrual loans
Total loans, before unearned income	9,209,593	7,591,799
Unearned income	(3,492)	(3,825)
Loans, net of unearned income	9,206,101	7,587,974
Non purchased loans and leases | Commercial, financial, agricultural
Past due and nonaccrual loans
Total loans, before unearned income	2,416,243	1,052,353
Non purchased loans and leases | Lease financing
Past due and nonaccrual loans
Total loans, before unearned income	84,271	85,700
Non purchased loans and leases | Real estate – construction:
Past due and nonaccrual loans
Total loans, before unearned income	756,872	774,901
Non purchased loans and leases | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Total loans, before unearned income	2,342,987	2,350,126
Non purchased loans and leases | Real estate – commercial mortgage:
Past due and nonaccrual loans
Total loans, before unearned income	3,400,718	3,128,876
Non purchased loans and leases | Installment loans to individuals
Past due and nonaccrual loans
Total loans, before unearned income	208,502	199,843
Non purchased loans and leases | Accruing Loans
Past due and nonaccrual loans
Unearned income	(3,492)	(3,825)
Current Loans	9,178,931	7,540,226
Loans, net of unearned income	9,189,510	7,566,465
Non purchased loans and leases | Accruing Loans | Commercial, financial, agricultural
Past due and nonaccrual loans
Current, gross	2,411,443	1,045,802
Total loans, before unearned income	2,412,795	1,046,883
Non purchased loans and leases | Accruing Loans | Lease financing
Past due and nonaccrual loans
Current, gross	84,120	85,474
Total loans, before unearned income	84,120	85,474
Non purchased loans and leases | Accruing Loans | Real estate – construction:
Past due and nonaccrual loans
Current, gross	756,722	774,107
Total loans, before unearned income	756,872	774,901
Non purchased loans and leases | Accruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Current, gross	2,327,535	2,320,328
Total loans, before unearned income	2,334,716	2,340,850
Non purchased loans and leases | Accruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Current, gross	3,394,993	3,119,785
Total loans, before unearned income	3,396,175	3,122,423
Non purchased loans and leases | Accruing Loans | Installment loans to individuals
Past due and nonaccrual loans
Current, gross	207,610	198,555
Total loans, before unearned income	208,324	199,759
Non purchased loans and leases | Nonaccruing Loans
Past due and nonaccrual loans
Current Loans	7,142	3,635
Loans, net of unearned income	16,591	21,509
Non purchased loans and leases | Nonaccruing Loans | Commercial, financial, agricultural
Past due and nonaccrual loans
Current, gross	1,458	60
Total loans, before unearned income	3,448	5,470
Non purchased loans and leases | Nonaccruing Loans | Lease financing
Past due and nonaccrual loans
Current, gross	151	0
Total loans, before unearned income	151	226
Non purchased loans and leases | Nonaccruing Loans | Real estate – construction:
Past due and nonaccrual loans
Current, gross	0	0
Total loans, before unearned income	0	0
Non purchased loans and leases | Nonaccruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Current, gross	4,616	2,082
Total loans, before unearned income	8,271	9,276
Non purchased loans and leases | Nonaccruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Current, gross	879	1,426
Total loans, before unearned income	4,543	6,453
Non purchased loans and leases | Nonaccruing Loans | Installment loans to individuals
Past due and nonaccrual loans
Current, gross	38	67
Total loans, before unearned income	178	84
Non purchased loans and leases | 30-89 Days Past Due | Accruing Loans
Past due and nonaccrual loans
Loans past due	6,586	22,781
Non purchased loans and leases | 30-89 Days Past Due | Accruing Loans | Commercial, financial, agricultural
Past due and nonaccrual loans
Past due, gross	576	605
Non purchased loans and leases | 30-89 Days Past Due | Accruing Loans | Lease financing
Past due and nonaccrual loans
Past due, gross	0	0
Non purchased loans and leases | 30-89 Days Past Due | Accruing Loans | Real estate – construction:
Past due and nonaccrual loans
Past due, gross	150	794
Non purchased loans and leases | 30-89 Days Past Due | Accruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Past due, gross	4,302	18,020
Non purchased loans and leases | 30-89 Days Past Due | Accruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Past due, gross	976	2,362
Non purchased loans and leases | 30-89 Days Past Due | Accruing Loans | Installment loans to individuals
Past due and nonaccrual loans
Past due, gross	582	1,000
Non purchased loans and leases | 30-89 Days Past Due | Nonaccruing Loans
Past due and nonaccrual loans
Loans past due	305	1,382
Non purchased loans and leases | 30-89 Days Past Due | Nonaccruing Loans | Commercial, financial, agricultural
Past due and nonaccrual loans
Past due, gross	0	387
Non purchased loans and leases | 30-89 Days Past Due | Nonaccruing Loans | Lease financing
Past due and nonaccrual loans
Past due, gross	0	0
Non purchased loans and leases | 30-89 Days Past Due | Nonaccruing Loans | Real estate – construction:
Past due and nonaccrual loans
Past due, gross	0	0
Non purchased loans and leases | 30-89 Days Past Due | Nonaccruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Past due, gross	206	623
Non purchased loans and leases | 30-89 Days Past Due | Nonaccruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Past due, gross	99	372
Non purchased loans and leases | 30-89 Days Past Due | Nonaccruing Loans | Installment loans to individuals
Past due and nonaccrual loans
Past due, gross	0	0
Non purchased loans and leases | 90 Days or More Past Due | Accruing Loans
Past due and nonaccrual loans
Loans past due	3,993	3,458
Non purchased loans and leases | 90 Days or More Past Due | Accruing Loans | Commercial, financial, agricultural
Past due and nonaccrual loans
Past due, gross	776	476
Non purchased loans and leases | 90 Days or More Past Due | Accruing Loans | Lease financing
Past due and nonaccrual loans
Past due, gross	0	0
Non purchased loans and leases | 90 Days or More Past Due | Accruing Loans | Real estate – construction:
Past due and nonaccrual loans
Past due, gross	0	0
Non purchased loans and leases | 90 Days or More Past Due | Accruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Past due, gross	2,879	2,502
Non purchased loans and leases | 90 Days or More Past Due | Accruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Past due, gross	206	276
Non purchased loans and leases | 90 Days or More Past Due | Accruing Loans | Installment loans to individuals
Past due and nonaccrual loans
Past due, gross	132	204
Non purchased loans and leases | 90 Days or More Past Due | Nonaccruing Loans
Past due and nonaccrual loans
Loans past due	9,144	16,492
Non purchased loans and leases | 90 Days or More Past Due | Nonaccruing Loans | Commercial, financial, agricultural
Past due and nonaccrual loans
Past due, gross	1,990	5,023
Non purchased loans and leases | 90 Days or More Past Due | Nonaccruing Loans | Lease financing
Past due and nonaccrual loans
Past due, gross	0	226
Non purchased loans and leases | 90 Days or More Past Due | Nonaccruing Loans | Real estate – construction:
Past due and nonaccrual loans
Past due, gross	0	0
Non purchased loans and leases | 90 Days or More Past Due | Nonaccruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Past due, gross	3,449	6,571
Non purchased loans and leases | 90 Days or More Past Due | Nonaccruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Past due, gross	3,565	4,655
Non purchased loans and leases | 90 Days or More Past Due | Nonaccruing Loans | Installment loans to individuals
Past due and nonaccrual loans
Past due, gross	140	17
Non purchased loans and leases | Residential | Real estate – construction:
Past due and nonaccrual loans
Total loans, before unearned income	291,983	272,643
Non purchased loans and leases | Residential | Accruing Loans | Real estate – construction:
Past due and nonaccrual loans
Current, gross	291,833
Total loans, before unearned income	291,983
Non purchased loans and leases | Residential | Nonaccruing Loans | Real estate – construction:
Past due and nonaccrual loans
Current, gross	0
Total loans, before unearned income	0
Non purchased loans and leases | Residential | 30-89 Days Past Due | Accruing Loans | Real estate – construction:
Past due and nonaccrual loans
Past due, gross	150
Non purchased loans and leases | Residential | 30-89 Days Past Due | Nonaccruing Loans | Real estate – construction:
Past due and nonaccrual loans
Past due, gross	0
Non purchased loans and leases | Residential | 90 Days or More Past Due | Accruing Loans | Real estate – construction:
Past due and nonaccrual loans
Past due, gross	0
Non purchased loans and leases | Residential | 90 Days or More Past Due | Nonaccruing Loans | Real estate – construction:
Past due and nonaccrual loans
Past due, gross	0
Non purchased loans and leases | Commercial | Real estate – construction:
Past due and nonaccrual loans
Total loans, before unearned income	464,889	502,258
Non purchased loans and leases | Commercial | Accruing Loans | Real estate – construction:
Past due and nonaccrual loans
Current, gross	464,889
Total loans, before unearned income	464,889
Non purchased loans and leases | Commercial | Nonaccruing Loans | Real estate – construction:
Past due and nonaccrual loans
Current, gross	0
Total loans, before unearned income	0
Non purchased loans and leases | Commercial | 30-89 Days Past Due | Accruing Loans | Real estate – construction:
Past due and nonaccrual loans
Past due, gross	0
Non purchased loans and leases | Commercial | 30-89 Days Past Due | Nonaccruing Loans | Real estate – construction:
Past due and nonaccrual loans
Past due, gross	0
Non purchased loans and leases | Commercial | 90 Days or More Past Due | Accruing Loans | Real estate – construction:
Past due and nonaccrual loans
Past due, gross	0
Non purchased loans and leases | Commercial | 90 Days or More Past Due | Nonaccruing Loans | Real estate – construction:
Past due and nonaccrual loans
Past due, gross	0
Non purchased loans and leases | Primary | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Total loans, before unearned income	1,476,196	1,449,219
Non purchased loans and leases | Primary | Accruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Current, gross	1,463,010
Total loans, before unearned income	1,468,927
Non purchased loans and leases | Primary | Nonaccruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Current, gross	4,156
Total loans, before unearned income	7,269
Non purchased loans and leases | Primary | 30-89 Days Past Due | Accruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Past due, gross	3,464
Non purchased loans and leases | Primary | 30-89 Days Past Due | Nonaccruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Past due, gross	206
Non purchased loans and leases | Primary | 90 Days or More Past Due | Accruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Past due, gross	2,453
Non purchased loans and leases | Primary | 90 Days or More Past Due | Nonaccruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Past due, gross	2,907
Non purchased loans and leases | Home equity | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Total loans, before unearned income	440,774	456,265
Non purchased loans and leases | Home equity | Accruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Current, gross	439,608
Total loans, before unearned income	440,288
Non purchased loans and leases | Home equity | Nonaccruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Current, gross	419
Total loans, before unearned income	486
Non purchased loans and leases | Home equity | 30-89 Days Past Due | Accruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Past due, gross	502
Non purchased loans and leases | Home equity | 30-89 Days Past Due | Nonaccruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Past due, gross	0
Non purchased loans and leases | Home equity | 90 Days or More Past Due | Accruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Past due, gross	178
Non purchased loans and leases | Home equity | 90 Days or More Past Due | Nonaccruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Past due, gross	67
Non purchased loans and leases | Rental/investment | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Total loans, before unearned income	277,647	291,931
Non purchased loans and leases | Rental/investment | Accruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Current, gross	276,631
Total loans, before unearned income	277,183
Non purchased loans and leases | Rental/investment | Nonaccruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Current, gross	7
Total loans, before unearned income	464
Non purchased loans and leases | Rental/investment | 30-89 Days Past Due | Accruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Past due, gross	304
Non purchased loans and leases | Rental/investment | 30-89 Days Past Due | Nonaccruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Past due, gross	0
Non purchased loans and leases | Rental/investment | 90 Days or More Past Due | Accruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Past due, gross	248
Non purchased loans and leases | Rental/investment | 90 Days or More Past Due | Nonaccruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Past due, gross	457
Non purchased loans and leases | Land development | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Total loans, before unearned income	148,370	152,711
Non purchased loans and leases | Land development | Real estate – commercial mortgage:
Past due and nonaccrual loans
Total loans, before unearned income	118,777	116,085
Non purchased loans and leases | Land development | Accruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Current, gross	148,286
Total loans, before unearned income	148,318
Non purchased loans and leases | Land development | Accruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Current, gross	118,543
Total loans, before unearned income	118,689
Non purchased loans and leases | Land development | Nonaccruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Current, gross	34
Total loans, before unearned income	52
Non purchased loans and leases | Land development | Nonaccruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Current, gross	0
Total loans, before unearned income	88
Non purchased loans and leases | Land development | 30-89 Days Past Due | Accruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Past due, gross	32
Non purchased loans and leases | Land development | 30-89 Days Past Due | Accruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Past due, gross	107
Non purchased loans and leases | Land development | 30-89 Days Past Due | Nonaccruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Past due, gross	0
Non purchased loans and leases | Land development | 30-89 Days Past Due | Nonaccruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Past due, gross	0
Non purchased loans and leases | Land development | 90 Days or More Past Due | Accruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Past due, gross	0
Non purchased loans and leases | Land development | 90 Days or More Past Due | Accruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Past due, gross	39
Non purchased loans and leases | Land development | 90 Days or More Past Due | Nonaccruing Loans | Real estate – 1-4 family mortgage:
Past due and nonaccrual loans
Past due, gross	18
Non purchased loans and leases | Land development | 90 Days or More Past Due | Nonaccruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Past due, gross	88
Non purchased loans and leases | Owner-occupied | Real estate – commercial mortgage:
Past due and nonaccrual loans
Total loans, before unearned income	1,270,197	1,209,204
Non purchased loans and leases | Owner-occupied | Accruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Current, gross	1,265,911
Total loans, before unearned income	1,266,436
Non purchased loans and leases | Owner-occupied | Nonaccruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Current, gross	559
Total loans, before unearned income	3,761
Non purchased loans and leases | Owner-occupied | 30-89 Days Past Due | Accruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Past due, gross	419
Non purchased loans and leases | Owner-occupied | 30-89 Days Past Due | Nonaccruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Past due, gross	99
Non purchased loans and leases | Owner-occupied | 90 Days or More Past Due | Accruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Past due, gross	106
Non purchased loans and leases | Owner-occupied | 90 Days or More Past Due | Nonaccruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Past due, gross	3,103
Non purchased loans and leases | Non-owner occupied | Real estate – commercial mortgage:
Past due and nonaccrual loans
Total loans, before unearned income	2,011,744	$ 1,803,587
Non purchased loans and leases | Non-owner occupied | Accruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Current, gross	2,010,539
Total loans, before unearned income	2,011,050
Non purchased loans and leases | Non-owner occupied | Nonaccruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Current, gross	320
Total loans, before unearned income	694
Non purchased loans and leases | Non-owner occupied | 30-89 Days Past Due | Accruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Past due, gross	450
Non purchased loans and leases | Non-owner occupied | 30-89 Days Past Due | Nonaccruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Past due, gross	0
Non purchased loans and leases | Non-owner occupied | 90 Days or More Past Due | Accruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Past due, gross	61
Non purchased loans and leases | Non-owner occupied | 90 Days or More Past Due | Nonaccruing Loans | Real estate – commercial mortgage:
Past due and nonaccrual loans
Past due, gross	$ 374