LOANS - Loans by Risk Grade (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	$ 8,482,339	$ 8,511,914
Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	5,756,358	5,660,457
Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	2,472,271	2,588,832
1 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	540,646	542,164
1 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	80,682	90,775
2 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	587,622	523,101
2 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	84,904	84,617
3 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	2,372,115	2,408,128
3 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	677,718	656,289
4 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	2,088,813	2,047,688
4 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	1,428,353	1,586,377
5 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	87,785	59,054
5 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	90,391	63,613
6 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	32,949	35,118
6 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	38,599	30,448
7 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	46,428	45,204
7 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	71,618	76,713
8 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
8 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
9 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
9 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	6	0
Commercial, financial and agricultural | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	1,382,907	1,316,359
Commercial, financial and agricultural | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	327,972	372,686
Commercial, financial and agricultural | 1 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	528,386	530,864
Commercial, financial and agricultural | 1 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	80,138	90,205
Commercial, financial and agricultural | 2 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	521,486	452,250
Commercial, financial and agricultural | 2 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	5,313	2,648
Commercial, financial and agricultural | 3 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	152,722	174,811
Commercial, financial and agricultural | 3 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	20,562	20,489
Commercial, financial and agricultural | 4 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	161,089	137,038
Commercial, financial and agricultural | 4 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	168,472	215,096
Commercial, financial and agricultural | 5 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	13,131	13,714
Commercial, financial and agricultural | 5 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	22,982	14,445
Commercial, financial and agricultural | 6 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	3,557	5,130
Commercial, financial and agricultural | 6 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	10,614	11,601
Commercial, financial and agricultural | 7 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	2,536	2,552
Commercial, financial and agricultural | 7 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	19,891	18,202
Commercial, financial and agricultural | 8 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Commercial, financial and agricultural | 8 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Commercial, financial and agricultural | 9 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Commercial, financial and agricultural | 9 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Real estate – construction and development | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	676,563	671,198
Real estate – construction and development | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	239,413	227,900
Real estate – construction and development | 1 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	40
Real estate – construction and development | 1 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Real estate – construction and development | 2 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	516	681
Real estate – construction and development | 2 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Real estate – construction and development | 3 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	66,180	74,657
Real estate – construction and development | 3 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	12,759	18,022
Real estate – construction and development | 4 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	593,309	582,456
Real estate – construction and development | 4 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	207,413	195,079
Real estate – construction and development | 5 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	11,560	6,264
Real estate – construction and development | 5 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	4,765	2,728
Real estate – construction and development | 6 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	1,415	4,091
Real estate – construction and development | 6 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	4,598	1,459
Real estate – construction and development | 7 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	3,583	3,009
Real estate – construction and development | 7 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	9,878	10,612
Real estate – construction and development | 8 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Real estate – construction and development | 8 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Real estate – construction and development | 9 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Real estate – construction and development | 9 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Real estate – commercial and farmland | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	1,894,937	1,814,529
Real estate – commercial and farmland | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	1,280,515	1,337,859
Real estate – commercial and farmland | 1 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	724	500
Real estate – commercial and farmland | 1 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Real estate – commercial and farmland | 2 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	33,656	37,079
Real estate – commercial and farmland | 2 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	9,446	7,407
Real estate – commercial and farmland | 3 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	923,222	888,433
Real estate – commercial and farmland | 3 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	270,517	230,089
Real estate – commercial and farmland | 4 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	834,693	814,068
Real estate – commercial and farmland | 4 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	913,144	1,034,943
Real estate – commercial and farmland | 5 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	56,333	30,364
Real estate – commercial and farmland | 5 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	48,763	29,468
Real estate – commercial and farmland | 6 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	23,534	20,959
Real estate – commercial and farmland | 6 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	15,816	10,063
Real estate – commercial and farmland | 7 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	22,775	23,126
Real estate – commercial and farmland | 7 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	22,829	25,889
Real estate – commercial and farmland | 8 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Real estate – commercial and farmland | 8 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Real estate – commercial and farmland | 9 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Real estate – commercial and farmland | 9 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Real estate – residential | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	1,365,482	1,403,000
Real estate – residential | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	597,735	623,199
Real estate – residential | 1 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	694	16
Real estate – residential | 1 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Real estate – residential | 2 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	31,944	33,043
Real estate – residential | 2 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	70,003	74,398
Real estate – residential | 3 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	1,206,722	1,246,383
Real estate – residential | 3 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	371,501	385,279
Real estate – residential | 4 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	98,050	94,143
Real estate – residential | 4 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	116,762	118,082
Real estate – residential | 5 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	6,741	8,634
Real estate – residential | 5 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	13,847	16,937
Real estate – residential | 6 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	4,372	4,881
Real estate – residential | 6 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	7,441	7,231
Real estate – residential | 7 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	16,959	15,900
Real estate – residential | 7 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	18,181	21,272
Real estate – residential | 8 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Real estate – residential | 8 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Real estate – residential | 9 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Real estate – residential | 9 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Consumer installment | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	436,469	455,371
Consumer installment | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	26,636	27,188
Consumer installment | 1 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	10,842	10,744
Consumer installment | 1 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	544	570
Consumer installment | 2 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	20	48
Consumer installment | 2 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	142	164
Consumer installment | 3 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	23,269	23,844
Consumer installment | 3 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	2,379	2,410
Consumer installment | 4 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	401,672	419,983
Consumer installment | 4 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	22,562	23,177
Consumer installment | 5 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	20	78
Consumer installment | 5 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	34	35
Consumer installment | 6 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	71	57
Consumer installment | 6 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	130	94
Consumer installment | 7 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	575	617
Consumer installment | 7 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	839	738
Consumer installment | 8 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Consumer installment | 8 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Consumer installment | 9 | Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	0	0
Consumer installment | 9 | Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	$ 6	$ 0