LOANS AND ALLOWANCE FOR CREDIT LOSSES - Summary of Information Pertaining to Impaired Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	$ 71,878	$ 123,082
Allowance for Credit Losses	13,298	24,656
Commercial, financial and agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	2,870	5,490
Allowance for Credit Losses	704	2,252
Premium finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	2,315	3,523
Allowance for Credit Losses	97	0
Real estate – construction and development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	1,316	4,173
Allowance for Credit Losses	212	512
Real estate – commercial and farmland
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	50,744	100,180
Allowance for Credit Losses	10,161	21,001
Real estate – residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance	14,633	9,716
Allowance for Credit Losses	$ 2,124	$ 891