LOANS AND ALLOWANCE FOR LOAN LOSSES - Loans Receivable, Purchased Loans (Details) - Purchased Loans - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 861,595	$ 1,069,191
Commercial, financial and agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	74,378	96,537
Real estate – construction and development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	65,513	81,368
Real estate – commercial and farmland
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	468,246	576,355
Real estate – residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	250,539	310,277
Consumer installment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 2,919	$ 4,654