LOANS AND ALLOWANCE FOR CREDIT LOSSES - Analysis of Past-Due Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Financing Receivable, Past Due [Line Items]
Total Loans	$ 17,561,022	$ 15,874,258
Loans 90 Days or More Past Due and Still Accruing	8,542	12,648
Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	206,389	148,707
Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	60,951	54,024
Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	36,887	14,215
Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	108,552	80,468
Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	17,354,633	15,725,551
Commercial, financial and agricultural
Financing Receivable, Past Due [Line Items]
Total Loans	2,022,845	1,875,993
Loans 90 Days or More Past Due and Still Accruing	1,697	1,165
Commercial, financial and agricultural | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	18,610	17,453
Commercial, financial and agricultural | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	3,822	3,431
Commercial, financial and agricultural | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	3,725	2,005
Commercial, financial and agricultural | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	11,063	12,017
Commercial, financial and agricultural | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	2,004,235	1,858,540
Consumer installment
Financing Receivable, Past Due [Line Items]
Total Loans	167,237	191,298
Loans 90 Days or More Past Due and Still Accruing	466	584
Consumer installment | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	2,570	3,548
Consumer installment | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	1,132	1,786
Consumer installment | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	739	871
Consumer installment | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	699	891
Consumer installment | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	164,667	187,750
Indirect automobile
Financing Receivable, Past Due [Line Items]
Total Loans	172,245	265,779
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	827	1,430
Indirect automobile | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	394	772
Indirect automobile | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	137	185
Indirect automobile | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	296	473
Indirect automobile | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	171,418	264,349
Mortgage warehouse
Financing Receivable, Past Due [Line Items]
Total Loans	949,191	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	949,191	787,837
Municipal
Financing Receivable, Past Due [Line Items]
Total Loans	529,268	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	529,268	572,701
Premium finance
Financing Receivable, Past Due [Line Items]
Total Loans	942,357	798,409
Loans 90 Days or More Past Due and Still Accruing	5,795	9,134
Premium finance | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	19,655	20,466
Premium finance | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	7,462	6,992
Premium finance | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	6,398	4,340
Premium finance | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	5,795	9,134
Premium finance | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	922,702	777,943
Real estate – construction and development
Financing Receivable, Past Due [Line Items]
Total Loans	1,747,284	1,452,339
Loans 90 Days or More Past Due and Still Accruing	584	1,758
Real estate – construction and development | Total Loans Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	24,360	20,189
Real estate – construction and development | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	18,050	16,601
Real estate – construction and development | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	5,677	1,398
Real estate – construction and development | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	633	2,190
Real estate – construction and development | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	1,722,924	1,432,150
Real estate – commercial and farmland
Financing Receivable, Past Due [Line Items]
Total Loans	7,156,017	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	17,705	13,787
Real estate – commercial and farmland | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	2,706	6,713
Real estate – commercial and farmland | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	11,334	1,150
Real estate – commercial and farmland | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	3,666	5,924
Real estate – commercial and farmland | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	7,138,312	6,821,130
Real estate – residential
Financing Receivable, Past Due [Line Items]
Total Loans	3,874,578	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	122,662	71,834
Real estate – residential | Loans 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	27,385	17,729
Real estate – residential | Loans 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	8,877	4,266
Real estate – residential | Loans 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	86,400	49,839
Real estate – residential | Current Loans
Financing Receivable, Past Due [Line Items]
Total Loans	$ 3,751,916	$ 3,023,151