LOANS AND ALLOWANCE FOR CREDIT LOSSES - Loans by Risk Grade (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	$ 1,540,137	$ 5,989,264
Year two	5,406,141	2,709,114
Year three	2,600,483	1,925,433
Year four	1,791,900	1,037,226
Year five	927,504	898,344
Prior	2,572,066	1,925,757
Revolving Loans Amortized Cost Basis	1,305,570	1,389,120
Loans, net of unearned income	16,143,801	15,874,258
9
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Commercial, financial and agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	215,672	913,036
Year two	765,255	280,305
Year three	242,008	193,301
Year four	166,910	120,512
Year five	101,317	53,671
Prior	79,987	48,227
Revolving Loans Amortized Cost Basis	265,514	266,941
Loans, net of unearned income	1,836,663	1,875,993
Commercial, financial and agricultural | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	208,664	903,630
Year two	764,033	279,037
Year three	240,671	188,810
Year four	163,163	118,613
Year five	99,436	50,737
Prior	70,393	40,376
Revolving Loans Amortized Cost Basis	261,941	262,951
Loans, net of unearned income	1,808,301	1,844,154
Commercial, financial and agricultural | 6
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	0	190
Year two	167	0
Year three	92	393
Year four	93	427
Year five	156	368
Prior	2,551	1,832
Revolving Loans Amortized Cost Basis	541	1,961
Loans, net of unearned income	3,600	5,171
Commercial, financial and agricultural | 7
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	7,008	9,216
Year two	1,055	1,268
Year three	1,245	4,098
Year four	3,654	1,472
Year five	1,725	2,566
Prior	7,043	6,019
Revolving Loans Amortized Cost Basis	3,032	2,029
Loans, net of unearned income	24,762	26,668
Consumer installment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	18,548	35,840
Year two	21,392	59,504
Year three	51,765	37,485
Year four	32,840	27,482
Year five	24,498	9,890
Prior	19,200	11,561
Revolving Loans Amortized Cost Basis	5,399	9,536
Loans, net of unearned income	173,642	191,298
Consumer installment | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	18,541	35,781
Year two	21,321	59,221
Year three	51,632	37,195
Year four	32,530	27,266
Year five	24,305	9,787
Prior	18,621	11,021
Revolving Loans Amortized Cost Basis	5,259	9,437
Loans, net of unearned income	172,209	189,708
Consumer installment | 6
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Year five	0	0
Prior	133	135
Revolving Loans Amortized Cost Basis	5	5
Loans, net of unearned income	138	140
Consumer installment | 7
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	7	59
Year two	71	283
Year three	133	290
Year four	310	216
Year five	193	103
Prior	446	405
Revolving Loans Amortized Cost Basis	135	94
Loans, net of unearned income	1,295	1,450
Indirect automobile
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	0	0
Year two	0	0
Year three	0	20,331
Year four	17,448	102,227
Year five	86,477	90,688
Prior	110,195	52,533
Revolving Loans Amortized Cost Basis	0	0
Loans, net of unearned income	214,120	265,779
Indirect automobile | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	0	0
Year two	0	0
Year three	0	20,276
Year four	17,396	101,969
Year five	86,176	90,294
Prior	108,956	51,468
Revolving Loans Amortized Cost Basis	0	0
Loans, net of unearned income	212,528	264,007
Indirect automobile | 6
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	0	0
Year two	0	0
Year three	0	0
Year four	0	24
Year five	8	10
Prior	25	19
Revolving Loans Amortized Cost Basis	0	0
Loans, net of unearned income	33	53
Indirect automobile | 7
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	0	0
Year two	0	0
Year three	0	55
Year four	52	234
Year five	293	384
Prior	1,214	1,046
Revolving Loans Amortized Cost Basis	0	0
Loans, net of unearned income	1,559	1,719
Mortgage warehouse
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Year five	0	0
Prior	0	0
Revolving Loans Amortized Cost Basis	732,375	787,837
Loans, net of unearned income	732,375	787,837
Mortgage warehouse | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Year five	0	0
Prior	0	0
Revolving Loans Amortized Cost Basis	732,375	787,837
Loans, net of unearned income	732,375	787,837
Municipal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	2,184	44,727
Year two	43,031	219,385
Year three	213,311	14,831
Year four	13,860	5,494
Year five	5,119	109,040
Prior	270,421	179,224
Revolving Loans Amortized Cost Basis	0	0
Loans, net of unearned income	547,926	572,701
Municipal | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	2,184	44,727
Year two	43,031	219,385
Year three	213,311	14,831
Year four	13,860	5,494
Year five	5,119	109,040
Prior	270,421	179,224
Revolving Loans Amortized Cost Basis	0	0
Loans, net of unearned income	547,926	572,701
Premium finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	411,397	796,923
Year two	407,363	1,154
Year three	214	26
Year four	0	0
Year five	0	302
Prior	189	4
Revolving Loans Amortized Cost Basis	0	0
Loans, net of unearned income	819,163	798,409
Premium finance | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	411,397	787,884
Year two	402,635	1,059
Year three	214	26
Year four	0	0
Year five	0	302
Prior	189	4
Revolving Loans Amortized Cost Basis	0	0
Loans, net of unearned income	814,435	789,275
Premium finance | 7
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	0	9,039
Year two	4,728	95
Year three	0	0
Year four	0	0
Year five	0	0
Prior	0	0
Revolving Loans Amortized Cost Basis	0	0
Loans, net of unearned income	4,728	9,134
Real estate – construction and development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	168,867	833,764
Year two	872,850	292,041
Year three	262,345	176,483
Year four	147,425	53,509
Year five	35,710	24,590
Prior	67,900	47,626
Revolving Loans Amortized Cost Basis	22,118	24,326
Loans, net of unearned income	1,577,215	1,452,339
Real estate – construction and development | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	167,646	826,094
Year two	863,262	290,814
Year three	261,650	176,476
Year four	147,418	35,773
Year five	16,040	24,533
Prior	65,629	44,514
Revolving Loans Amortized Cost Basis	22,118	21,267
Loans, net of unearned income	1,543,763	1,419,471
Real estate – construction and development | 6
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	1,221	6,527
Year two	9,210	549
Year three	484	0
Year four	0	15,260
Year five	6,798	0
Prior	1,276	2,101
Revolving Loans Amortized Cost Basis	0	0
Loans, net of unearned income	18,989	24,437
Real estate – construction and development | 7
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	0	1,143
Year two	378	678
Year three	211	7
Year four	7	2,476
Year five	12,872	57
Prior	995	1,011
Revolving Loans Amortized Cost Basis	0	3,059
Loans, net of unearned income	14,463	8,431
Real estate – commercial and farmland
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	439,047	2,191,416
Year two	2,084,325	1,208,260
Year three	1,206,175	1,131,384
Year four	1,079,840	566,131
Year five	524,967	496,672
Prior	1,523,712	1,160,655
Revolving Loans Amortized Cost Basis	66,409	80,399
Loans, net of unearned income	6,924,475	6,834,917
Real estate – commercial and farmland | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	439,047	2,186,291
Year two	2,079,527	1,205,578
Year three	1,203,580	1,119,239
Year four	1,074,253	542,295
Year five	514,681	486,477
Prior	1,464,276	1,103,675
Revolving Loans Amortized Cost Basis	66,390	80,379
Loans, net of unearned income	6,841,754	6,723,934
Real estate – commercial and farmland | 6
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	0	416
Year two	0	0
Year three	0	1,036
Year four	0	14,760
Year five	676	5,334
Prior	22,416	21,665
Revolving Loans Amortized Cost Basis	0	0
Loans, net of unearned income	23,092	43,211
Real estate – commercial and farmland | 7
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	0	4,709
Year two	4,798	2,682
Year three	2,595	11,109
Year four	5,587	9,076
Year five	9,610	4,861
Prior	37,020	35,315
Revolving Loans Amortized Cost Basis	19	20
Loans, net of unearned income	59,629	67,772
Real estate – residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	284,422	1,173,558
Year two	1,211,925	648,465
Year three	624,665	351,592
Year four	333,577	161,871
Year five	149,416	113,491
Prior	500,462	425,927
Revolving Loans Amortized Cost Basis	213,755	220,081
Loans, net of unearned income	3,318,222	3,094,985
Real estate – residential | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	284,325	1,171,008
Year two	1,205,153	638,232
Year three	606,135	329,247
Year four	308,373	149,990
Year five	136,724	108,538
Prior	474,015	408,240
Revolving Loans Amortized Cost Basis	211,941	217,982
Loans, net of unearned income	3,226,666	3,023,237
Real estate – residential | 6
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	64	145
Year two	143	66
Year three	65	1,106
Year four	1,092	505
Year five	495	356
Prior	3,909	3,717
Revolving Loans Amortized Cost Basis	48	49
Loans, net of unearned income	5,816	5,944
Real estate – residential | 7
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	33	2,405
Year two	6,629	10,167
Year three	18,465	21,239
Year four	24,112	11,376
Year five	12,197	4,597
Prior	22,538	13,970
Revolving Loans Amortized Cost Basis	1,766	2,050
Loans, net of unearned income	85,740	65,804
Total Loans | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	1,531,804	5,955,415
Year two	5,378,962	2,693,326
Year three	2,577,193	1,886,100
Year four	1,756,993	981,400
Year five	882,481	879,708
Prior	2,472,500	1,838,522
Revolving Loans Amortized Cost Basis	1,300,024	1,379,853
Loans, net of unearned income	15,899,957	15,614,324
Total Loans | 6
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	1,285	7,278
Year two	9,520	615
Year three	641	2,535
Year four	1,185	30,976
Year five	8,133	6,068
Prior	30,310	29,469
Revolving Loans Amortized Cost Basis	594	2,015
Loans, net of unearned income	51,668	78,956
Total Loans | 7
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one	7,048	26,571
Year two	17,659	15,173
Year three	22,649	36,798
Year four	33,722	24,850
Year five	36,890	12,568
Prior	69,256	57,766
Revolving Loans Amortized Cost Basis	4,952	7,252
Loans, net of unearned income	$ 192,176	$ 180,978