LOANS - Modifications of Loans Performing (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment	$ 3,123,678	$ 2,600,358
TDRs [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	6,201	6,824	$ 5,307
Past Due 30-89	321	985	732
Past Due 90 days and still accruing	0	167	0
Nonaccrual	21,002	23,993	8,257
Recorded Investment	27,524	31,969	14,295
Allowance for loan losses, Current Loans	163	128	80
Allowance for loan losses, Past Due 30-89	29	0	13
Allowance for loan losses, Past Due 90 days and still accruing	0	0	0
Allowance for loan losses, Non-Accrual	3,936	1,997	110
Allowance for loan losses, Total	4,128	2,125	203
Commercial financial and agriculture | TDRs [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	59	583	13
Past Due 30-89	0	64	646
Past Due 90 days and still accruing	0	0	0
Nonaccrual	765	1,062	18
Recorded Investment	824	1,709	676
Commercial real estate | TDRs [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	4,560	4,299	4,827
Past Due 30-89	49	809	0
Past Due 90 days and still accruing	0	109	0
Nonaccrual	18,076	19,991	5,425
Recorded Investment	22,685	25,208	10,252
Consumer real estate | TDRs [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	1,559	1,905	442
Past Due 30-89	269	112	86
Past Due 90 days and still accruing	0	58	0
Nonaccrual	2,161	2,940	2,801
Recorded Investment	3,989	5,015	3,329
Consumer installment | TDRs [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	23	37	25
Past Due 30-89	3	0	0
Past Due 90 days and still accruing	0	0	0
Nonaccrual	0	0	13
Recorded Investment	$ 26	$ 37	$ 38