LOANS AND ALLOWANCE FOR LOAN LOSSES - Loans Receivable, Excluding Purchased Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	$ 12,818,476	$ 8,511,914
Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	7,529,987	5,660,457
Commercial, financial and agricultural | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	1,646,438	1,316,359
Real estate – construction and development | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	1,083,564	671,198
Real estate – commercial and farmland | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	2,447,834	1,814,529
Real estate – residential | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	1,901,352	1,403,000
Consumer installment | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	$ 450,799	$ 455,371