LOANS AND ALLOWANCE FOR CREDIT LOSSES - Analysis of Past-Due Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Financing Receivable, Past Due [Line Items]
Total Loans	$ 20,964,981	$ 20,269,303
Loans 90 Days or More Past Due and Still Accruing	12,234	16,988
Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	216,603	272,839
Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	96,485	82,850
Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	34,358	34,281
Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	85,760	155,708
Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	20,748,378	19,996,464
Commercial, financial and agricultural
Financing Receivable, Past Due [Line Items]
Total Loans	2,949,957	2,688,929
Loans 90 Days or More Past Due and Still Accruing	4,732	5,310
Commercial, financial and agricultural | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	35,519	26,195
Commercial, financial and agricultural | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	20,313	11,023
Commercial, financial and agricultural | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	6,299	5,439
Commercial, financial and agricultural | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	8,907	9,733
Commercial, financial and agricultural | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	2,914,438	2,662,734
Consumer
Financing Receivable, Past Due [Line Items]
Total Loans	210,310	241,552
Loans 90 Days or More Past Due and Still Accruing	0	0
Consumer | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	2,789	3,690
Consumer | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	1,911	2,155
Consumer | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	512	1,037
Consumer | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	366	498
Consumer | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	207,521	237,862
Indirect automobile
Financing Receivable, Past Due [Line Items]
Total Loans	10,891	34,257
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	126	248
Indirect automobile | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	51	153
Indirect automobile | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	24	17
Indirect automobile | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	51	78
Indirect automobile | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	10,765	34,009
Mortgage warehouse
Financing Receivable, Past Due [Line Items]
Total Loans	985,910	818,728
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	985,910	818,728
Municipal
Financing Receivable, Past Due [Line Items]
Total Loans	449,561	492,668
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	449,561	492,668
Premium finance
Financing Receivable, Past Due [Line Items]
Total Loans	1,246,452	946,562
Loans 90 Days or More Past Due and Still Accruing	7,502	11,678
Premium finance | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	26,628	30,889
Premium finance | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	13,246	12,379
Premium finance | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	5,880	6,832
Premium finance | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	7,502	11,678
Premium finance | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	1,219,824	915,673
Real estate – construction and development
Financing Receivable, Past Due [Line Items]
Total Loans	2,232,114	2,129,187
Loans 90 Days or More Past Due and Still Accruing	0	0
Real estate – construction and development | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	14,682	2,376
Real estate – construction and development | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	10,411	2,094
Real estate – construction and development | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	3,687	0
Real estate – construction and development | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	584	282
Real estate – construction and development | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	2,217,432	2,126,811
Real estate – commercial and farmland
Financing Receivable, Past Due [Line Items]
Total Loans	8,249,981	8,059,754
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	15,209	13,078
Real estate – commercial and farmland | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	4,514	5,070
Real estate – commercial and farmland | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	3,133	1,656
Real estate – commercial and farmland | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	7,562	6,352
Real estate – commercial and farmland | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	8,234,772	8,046,676
Real estate – residential
Financing Receivable, Past Due [Line Items]
Total Loans	4,629,805	4,857,666
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	121,650	196,363
Real estate – residential | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	46,039	49,976
Real estate – residential | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	14,823	19,300
Real estate – residential | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	60,788	127,087
Real estate – residential | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	$ 4,508,155	$ 4,661,303