LOANS AND ALLOWANCE FOR CREDIT LOSSES - Analysis of Past-Due Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Financing Receivable, Past Due [Line Items]
Total Loans	$ 20,471,759	$ 19,855,253
Loans 90 Days or More Past Due and Still Accruing	13,424	17,865
Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	221,902	273,465
Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	59,871	95,203
Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	31,520	34,637
Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	130,511	143,625
Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	20,249,857	19,581,788
Commercial, financial and agricultural
Financing Receivable, Past Due [Line Items]
Total Loans	2,718,831	2,679,403
Loans 90 Days or More Past Due and Still Accruing	4,385	3,267
Commercial, financial and agricultural | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	28,726	33,302
Commercial, financial and agricultural | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	12,380	16,219
Commercial, financial and agricultural | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	5,976	5,451
Commercial, financial and agricultural | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	10,370	11,632
Commercial, financial and agricultural | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	2,690,105	2,646,101
Consumer
Financing Receivable, Past Due [Line Items]
Total Loans	307,486	384,037
Loans 90 Days or More Past Due and Still Accruing	331	472
Consumer | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	6,361	6,443
Consumer | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	5,111	2,539
Consumer | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	815	3,163
Consumer | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	435	741
Consumer | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	301,125	377,594
Indirect automobile
Financing Receivable, Past Due [Line Items]
Total Loans	63,231	108,648
Loans 90 Days or More Past Due and Still Accruing	0	0
Indirect automobile | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	323	810
Indirect automobile | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	138	466
Indirect automobile | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	49	77
Indirect automobile | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	136	267
Indirect automobile | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	62,908	107,838
Mortgage warehouse
Financing Receivable, Past Due [Line Items]
Total Loans	1,147,413	1,038,924
Loans 90 Days or More Past Due and Still Accruing	0	0
Mortgage warehouse | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	0	0
Mortgage warehouse | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	0	0
Mortgage warehouse | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	0	0
Mortgage warehouse | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	0	0
Mortgage warehouse | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	1,147,413	1,038,924
Municipal
Financing Receivable, Past Due [Line Items]
Total Loans	510,410	509,151
Loans 90 Days or More Past Due and Still Accruing	0	0
Municipal | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	0	0
Municipal | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	0	0
Municipal | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	0	0
Municipal | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	0	0
Municipal | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	510,410	509,151
Premium finance
Financing Receivable, Past Due [Line Items]
Total Loans	988,731	1,023,479
Loans 90 Days or More Past Due and Still Accruing	8,387	13,626
Premium finance | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	24,269	38,105
Premium finance | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	6,795	13,859
Premium finance | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	9,087	10,620
Premium finance | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	8,387	13,626
Premium finance | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	964,462	985,374
Real estate – construction and development
Financing Receivable, Past Due [Line Items]
Total Loans	2,217,744	2,086,438
Loans 90 Days or More Past Due and Still Accruing	321	500
Real estate – construction and development | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	1,844	30,162
Real estate – construction and development | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	1,061	25,367
Real estate – construction and development | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	19	3,829
Real estate – construction and development | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	764	966
Real estate – construction and development | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	2,215,900	2,056,276
Real estate – commercial and farmland
Financing Receivable, Past Due [Line Items]
Total Loans	7,815,779	7,604,867
Loans 90 Days or More Past Due and Still Accruing	0	0
Real estate – commercial and farmland | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	13,420	12,129
Real estate – commercial and farmland | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	2,782	1,738
Real estate – commercial and farmland | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	2,883	168
Real estate – commercial and farmland | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	7,755	10,223
Real estate – commercial and farmland | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	7,802,359	7,592,738
Real estate – residential
Financing Receivable, Past Due [Line Items]
Total Loans	4,702,134	4,420,306
Loans 90 Days or More Past Due and Still Accruing	0	0
Real estate – residential | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	146,959	152,514
Real estate – residential | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	31,604	35,015
Real estate – residential | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	12,691	11,329
Real estate – residential | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	102,664	106,170
Real estate – residential | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	$ 4,555,175	$ 4,267,792