LOANS AND ALLOWANCE FOR LOAN LOSSES - Loans Receivable, Purchased Loans (Details) - Purchased Loans - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 5,075,281	$ 2,588,832
Commercial, financial and agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	384,273	372,686
Real estate – construction and development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	465,497	227,900
Real estate – commercial and farmland
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,905,205	1,337,859
Real estate – residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,220,271	623,199
Consumer installment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 1,100,035	$ 27,188