LOANS - Deferrals Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Financing Receivable, Troubled Debt Restructuring [Line Items]
COVID-19 Deferrals	$ 235,421	$ 332,779
Deferrals as a % of total loans	1.60%	2.30%
Commercial, financial and agricultural
Financing Receivable, Troubled Debt Restructuring [Line Items]
COVID-19 Deferrals	$ 4,460	$ 12,471
Deferrals as a % of total loans	0.30%	0.80%
Consumer installment
Financing Receivable, Troubled Debt Restructuring [Line Items]
COVID-19 Deferrals	$ 569	$ 1,418
Deferrals as a % of total loans	0.20%	0.50%
Indirect automobile
Financing Receivable, Troubled Debt Restructuring [Line Items]
COVID-19 Deferrals	$ 3,536	$ 8,936
Deferrals as a % of total loans	0.70%	1.50%
Real estate – construction and development
Financing Receivable, Troubled Debt Restructuring [Line Items]
COVID-19 Deferrals	$ 418	$ 11,049
Deferrals as a % of total loans	0.00%	0.70%
Real estate – commercial and farmland
Financing Receivable, Troubled Debt Restructuring [Line Items]
COVID-19 Deferrals	$ 152,337	$ 179,183
Deferrals as a % of total loans	2.70%	3.40%
Real estate – residential
Financing Receivable, Troubled Debt Restructuring [Line Items]
COVID-19 Deferrals	$ 74,101	$ 119,722
Deferrals as a % of total loans	2.60%	4.30%