LOANS AND ALLOWANCE FOR LOAN LOSSES - Analysis of Past-Due Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	$ 8,511,914	$ 6,046,355
Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	53,984	44,215
Current Loans	5,606,473	4,812,299
Total Loans	5,660,457	4,856,514
Loans 90 Days or More Past Due and Still Accruing	4,222	5,991
Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	35,599	14,774
Current Loans	2,553,233	846,821
Total Loans	2,588,832	861,595
Loans 90 Days or More Past Due and Still Accruing	0	0
Loans 30-59 Days Past Due | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	23,089	20,131
Loans 30-59 Days Past Due | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	16,193	4,056
Loans 60-89 Days Past Due | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	12,104	7,508
Loans 60-89 Days Past Due | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	4,166	2,354
Loans 90 or More Days Past Due | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	18,791	16,576
Loans 90 or More Days Past Due | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	15,240	8,364
Commercial, financial and agricultural | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	16,537	18,387
Current Loans	1,299,822	1,344,121
Total Loans	1,316,359	1,362,508
Loans 90 Days or More Past Due and Still Accruing	3,808	5,991
Commercial, financial and agricultural | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	1,852	793
Current Loans	370,834	73,585
Total Loans	372,686	74,378
Loans 90 Days or More Past Due and Still Accruing	0	0
Commercial, financial and agricultural | Loans 30-59 Days Past Due | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	6,479	8,124
Commercial, financial and agricultural | Loans 30-59 Days Past Due | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	421	0
Commercial, financial and agricultural | Loans 60-89 Days Past Due | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	5,295	3,285
Commercial, financial and agricultural | Loans 60-89 Days Past Due | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	416	33
Commercial, financial and agricultural | Loans 90 or More Days Past Due | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	4,763	6,978
Commercial, financial and agricultural | Loans 90 or More Days Past Due | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	1,015	760
Real estate – construction and development | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	2,424	1,121
Current Loans	668,774	623,474
Total Loans	671,198	624,595
Loans 90 Days or More Past Due and Still Accruing	0	0
Real estate – construction and development | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	6,270	2,635
Current Loans	221,630	62,878
Total Loans	227,900	65,513
Loans 90 Days or More Past Due and Still Accruing	0	0
Real estate – construction and development | Loans 30-59 Days Past Due | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	1,218	810
Real estate – construction and development | Loans 30-59 Days Past Due | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	627	87
Real estate – construction and development | Loans 60-89 Days Past Due | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	481	23
Real estate – construction and development | Loans 60-89 Days Past Due | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	370	31
Real estate – construction and development | Loans 90 or More Days Past Due | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	725	288
Real estate – construction and development | Loans 90 or More Days Past Due | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	5,273	2,517
Real estate – commercial and farmland | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	5,800	3,596
Current Loans	1,808,729	1,531,843
Total Loans	1,814,529	1,535,439
Loans 90 Days or More Past Due and Still Accruing	0	0
Real estate – commercial and farmland | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	4,369	4,615
Current Loans	1,333,490	463,631
Total Loans	1,337,859	468,246
Loans 90 Days or More Past Due and Still Accruing	0	0
Real estate – commercial and farmland | Loans 30-59 Days Past Due | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	1,625	869
Real estate – commercial and farmland | Loans 30-59 Days Past Due | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	1,935	1,190
Real estate – commercial and farmland | Loans 60-89 Days Past Due | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	530	787
Real estate – commercial and farmland | Loans 60-89 Days Past Due | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	736	701
Real estate – commercial and farmland | Loans 90 or More Days Past Due | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	3,645	1,940
Real estate – commercial and farmland | Loans 90 or More Days Past Due | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	1,698	2,724
Real estate – residential | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	24,977	18,754
Current Loans	1,378,023	990,707
Total Loans	1,403,000	1,009,461
Loans 90 Days or More Past Due and Still Accruing	0	0
Real estate – residential | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	21,943	6,627
Current Loans	601,256	243,912
Total Loans	623,199	250,539
Loans 90 Days or More Past Due and Still Accruing	0	0
Real estate – residential | Loans 30-59 Days Past Due | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	11,423	8,772
Real estate – residential | Loans 30-59 Days Past Due | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	12,531	2,722
Real estate – residential | Loans 60-89 Days Past Due | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	4,631	2,941
Real estate – residential | Loans 60-89 Days Past Due | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	2,407	1,585
Real estate – residential | Loans 90 or More Days Past Due | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	8,923	7,041
Real estate – residential | Loans 90 or More Days Past Due | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	7,005	2,320
Consumer installment | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	4,246	2,357
Current Loans	451,125	322,154
Total Loans	455,371	324,511
Loans 90 Days or More Past Due and Still Accruing	414	0
Consumer installment | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	1,165	104
Current Loans	26,023	2,815
Total Loans	27,188	2,919
Loans 90 Days or More Past Due and Still Accruing	0	0
Consumer installment | Loans 30-59 Days Past Due | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	2,344	1,556
Consumer installment | Loans 30-59 Days Past Due | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	679	57
Consumer installment | Loans 60-89 Days Past Due | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	1,167	472
Consumer installment | Loans 60-89 Days Past Due | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	237	4
Consumer installment | Loans 90 or More Days Past Due | Loans Excluding Purchased Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	735	329
Consumer installment | Loans 90 or More Days Past Due | Purchased Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans Past Due	$ 249	$ 43