LOANS AND ALLOWANCE FOR LOAN LOSSES - Loans by Risk Grade (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	$ 6,046,355	$ 5,264,326
Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	4,856,514	3,626,821
Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	861,595	1,069,191
10 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	554,979	414,564
10 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	3,964	6,536
15 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	688,481	539,147
15 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	101,098	40,786
20 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	2,033,979	1,669,998
20 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	259,872	334,353
23 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	16,996	23,186
23 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	19,736	27,475
25 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	1,487,781	907,588
25 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	385,080	569,026
30 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	30,075	29,172
30 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	37,121	35,032
40 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	44,216	43,067
40 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	54,724	55,983
50 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	7	99
50 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
60 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
60 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Commercial, financial and agricultural | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	1,362,508	967,138
Commercial, financial and agricultural | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	74,378	96,537
Commercial, financial and agricultural | 10 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	539,899	397,093
Commercial, financial and agricultural | 10 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	3,358	5,722
Commercial, financial and agricultural | 15 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	568,557	376,323
Commercial, financial and agricultural | 15 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	4,541	1,266
Commercial, financial and agricultural | 20 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	125,740	97,057
Commercial, financial and agricultural | 20 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	8,517	16,204
Commercial, financial and agricultural | 23 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	330	366
Commercial, financial and agricultural | 23 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	22
Commercial, financial and agricultural | 25 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	117,358	92,066
Commercial, financial and agricultural | 25 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	43,085	67,123
Commercial, financial and agricultural | 30 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	5,236	144
Commercial, financial and agricultural | 30 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	13,718	5,072
Commercial, financial and agricultural | 40 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	5,381	4,089
Commercial, financial and agricultural | 40 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	1,159	1,128
Commercial, financial and agricultural | 50 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	7	0
Commercial, financial and agricultural | 50 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Commercial, financial and agricultural | 60 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Commercial, financial and agricultural | 60 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Real estate – construction and development | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	624,595	363,045
Real estate – construction and development | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	65,513	81,368
Real estate – construction and development | 10 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Real estate – construction and development | 10 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Real estate – construction and development | 15 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	1,005	5,390
Real estate – construction and development | 15 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Real estate – construction and development | 20 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	59,318	36,307
Real estate – construction and development | 20 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	13,014	10,686
Real estate – construction and development | 23 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	4,474	6,803
Real estate – construction and development | 23 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	2,306	3,643
Real estate – construction and development | 25 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	552,918	307,903
Real estate – construction and development | 25 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	39,877	56,006
Real estate – construction and development | 30 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	4,207	719
Real estate – construction and development | 30 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	4,076	7,271
Real estate – construction and development | 40 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	2,673	5,923
Real estate – construction and development | 40 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	6,240	3,762
Real estate – construction and development | 50 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Real estate – construction and development | 50 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Real estate – construction and development | 60 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Real estate – construction and development | 60 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Real estate – commercial and farmland | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	1,535,439	1,406,219
Real estate – commercial and farmland | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	468,246	576,355
Real estate – commercial and farmland | 10 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	5,790	8,814
Real estate – commercial and farmland | 10 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Real estate – commercial and farmland | 15 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	68,507	102,893
Real estate – commercial and farmland | 15 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	5,047	7,619
Real estate – commercial and farmland | 20 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	966,391	889,539
Real estate – commercial and farmland | 20 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	186,187	194,168
Real estate – commercial and farmland | 23 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	6,408	8,533
Real estate – commercial and farmland | 23 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	6,081	9,019
Real estate – commercial and farmland | 25 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	454,506	357,151
Real estate – commercial and farmland | 25 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	230,570	323,242
Real estate – commercial and farmland | 30 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	15,108	22,986
Real estate – commercial and farmland | 30 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	13,637	15,039
Real estate – commercial and farmland | 40 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	18,729	16,303
Real estate – commercial and farmland | 40 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	26,724	27,268
Real estate – commercial and farmland | 50 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Real estate – commercial and farmland | 50 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Real estate – commercial and farmland | 60 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Real estate – commercial and farmland | 60 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Real estate – residential | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	1,009,461	781,018
Real estate – residential | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	250,539	310,277
Real estate – residential | 10 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	47	125
Real estate – residential | 10 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Real estate – residential | 15 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	49,742	54,136
Real estate – residential | 15 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	91,270	31,331
Real estate – residential | 20 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	843,178	609,583
Real estate – residential | 20 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	50,988	111,712
Real estate – residential | 23 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	5,781	7,470
Real estate – residential | 23 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	11,349	14,791
Real estate – residential | 25 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	88,537	88,370
Real estate – residential | 25 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	70,837	121,379
Real estate – residential | 30 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	5,339	5,197
Real estate – residential | 30 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	5,637	7,605
Real estate – residential | 40 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	16,837	16,038
Real estate – residential | 40 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	20,458	23,459
Real estate – residential | 50 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	99
Real estate – residential | 50 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Real estate – residential | 60 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Real estate – residential | 60 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Consumer installment | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	309,194	96,915
Consumer installment | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	2,919	4,654
Consumer installment | 10 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	9,243	8,532
Consumer installment | 10 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	606	814
Consumer installment | 15 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	670	405
Consumer installment | 15 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	240	570
Consumer installment | 20 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	24,035	25,026
Consumer installment | 20 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	1,166	1,583
Consumer installment | 23 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	3	14
Consumer installment | 23 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Consumer installment | 25 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	274,462	62,098
Consumer installment | 25 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	711	1,276
Consumer installment | 30 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	185	126
Consumer installment | 30 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	53	45
Consumer installment | 40 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	596	714
Consumer installment | 40 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	143	366
Consumer installment | 50 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Consumer installment | 50 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Consumer installment | 60 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Consumer installment | 60 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Other | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	15,317	12,486
Other | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Other | 10 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Other | 10 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Other | 15 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Other | 15 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Other | 20 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	15,317	12,486
Other | 20 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Other | 23 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Other | 23 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Other | 25 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Other | 25 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Other | 30 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Other | 30 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Other | 40 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Other | 40 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Other | 50 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Other | 50 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Other | 60 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	0	0
Other | 60 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans portfolio by risk grade	$ 0	$ 0