LOANS AND ALLOWANCE FOR CREDIT LOSSES - Analysis of Past-Due Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Financing Receivable, Past Due [Line Items]
Total Loans	$ 18,806,856	$ 15,874,258
Loans 90 Days or More Past Due and Still Accruing	12,378	12,648
Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	215,877	148,707
Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	71,242	54,024
Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	21,556	14,215
Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	123,079	80,468
Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	18,590,979	15,725,551
Commercial, financial and agricultural
Financing Receivable, Past Due [Line Items]
Total Loans	2,245,287	1,875,993
Loans 90 Days or More Past Due and Still Accruing	2,075	1,165
Commercial, financial and agricultural | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	20,391	17,453
Commercial, financial and agricultural | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	7,515	3,431
Commercial, financial and agricultural | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	2,494	2,005
Commercial, financial and agricultural | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	10,382	12,017
Commercial, financial and agricultural | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	2,224,896	1,858,540
Consumer installment
Financing Receivable, Past Due [Line Items]
Total Loans	162,345	191,298
Loans 90 Days or More Past Due and Still Accruing	519	584
Consumer installment | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	2,848	3,548
Consumer installment | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	1,379	1,786
Consumer installment | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	763	871
Consumer installment | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	706	891
Consumer installment | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	159,497	187,750
Indirect automobile
Financing Receivable, Past Due [Line Items]
Total Loans	137,183	265,779
Loans 90 Days or More Past Due and Still Accruing		0
Indirect automobile | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	821	1,430
Indirect automobile | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	422	772
Indirect automobile | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	169	185
Indirect automobile | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	230	473
Indirect automobile | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	136,362	264,349
Mortgage warehouse
Financing Receivable, Past Due [Line Items]
Total Loans	980,342	787,837
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	980,342	787,837
Municipal
Financing Receivable, Past Due [Line Items]
Total Loans	516,797	572,701
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	516,797	572,701
Premium finance
Financing Receivable, Past Due [Line Items]
Total Loans	1,062,724	798,409
Loans 90 Days or More Past Due and Still Accruing	9,340	9,134
Premium finance | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	29,271	20,466
Premium finance | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	12,432	6,992
Premium finance | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	7,499	4,340
Premium finance | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	9,340	9,134
Premium finance | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	1,033,453	777,943
Real estate – construction and development
Financing Receivable, Past Due [Line Items]
Total Loans	2,009,726	1,452,339
Loans 90 Days or More Past Due and Still Accruing	444	1,758
Real estate – construction and development | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	22,925	20,189
Real estate – construction and development | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	20,430	16,601
Real estate – construction and development | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	2,003	1,398
Real estate – construction and development | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	492	2,190
Real estate – construction and development | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	1,986,801	1,432,150
Real estate – commercial and farmland
Financing Receivable, Past Due [Line Items]
Total Loans	7,516,309	6,834,917
Loans 90 Days or More Past Due and Still Accruing	0	7
Real estate – commercial and farmland | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	14,278	13,787
Real estate – commercial and farmland | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	2,465	6,713
Real estate – commercial and farmland | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	372	1,150
Real estate – commercial and farmland | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	11,441	5,924
Real estate – commercial and farmland | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	7,502,031	6,821,130
Real estate – residential
Financing Receivable, Past Due [Line Items]
Total Loans	4,176,143	3,094,985
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	125,343	71,834
Real estate – residential | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	26,599	17,729
Real estate – residential | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	8,256	4,266
Real estate – residential | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	90,488	49,839
Real estate – residential | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	$ 4,050,800	$ 3,023,151