LOANS AND ALLOWANCE FOR PROBABLE LOAN LOSSES - Troubled Debt Restructurings (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) contract	Dec. 31, 2017 USD ($) contract
Troubled Debt Restructuring [Abstract]
Extend Amortization Period	$ 10,617	$ 801
Interest Rate Reductions	112	0
Combination	540	293
Total Modifications	$ 11,269	$ 1,094
Number of Contracts | contract	22	10
1-4 Family Residential Real Estate Loans
Troubled Debt Restructuring [Abstract]
Extend Amortization Period	$ 0
Interest Rate Reductions	79
Combination	0
Total Modifications	$ 79
Number of Contracts | contract	1
Commercial Real Estate Loans
Troubled Debt Restructuring [Abstract]
Extend Amortization Period	$ 10,398
Interest Rate Reductions	0
Combination	274
Total Modifications	$ 10,672
Number of Contracts | contract	3
Commercial Loans
Troubled Debt Restructuring [Abstract]
Extend Amortization Period	$ 211	$ 778
Interest Rate Reductions	0	0
Combination	215	241
Total Modifications	$ 426	$ 1,019
Number of Contracts | contract	13	4
Loans to Individuals
Troubled Debt Restructuring [Abstract]
Extend Amortization Period	$ 8	$ 23
Interest Rate Reductions	33	0
Combination	51	52
Total Modifications	$ 92	$ 75
Number of Contracts | contract	5	6