LOANS - Loans Accounted for on a Nonaccrual Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 138,163	$ 75,124
Financing receivable, nonaccrual, no allowance	37,577
Commercial, financial and agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	11,844	9,236
Financing receivable, nonaccrual, no allowance	1,060
Consumer installment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	947	831
Indirect automobile
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	1,936	1,746
Premium finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	0	600
Real estate – construction and development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	5,666	1,988
Financing receivable, nonaccrual, no allowance	1,947
Real estate – commercial and farmland
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	39,248	23,797
Financing receivable, nonaccrual, no allowance	9,650
Real estate – residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	78,522	$ 36,926
Financing receivable, nonaccrual, no allowance	$ 24,920