LOANS AND ALLOWANCE FOR LOAN LOSSES - Summary of Impaired Loans (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2019	Dec. 31, 2018
Unpaid Principal Balance [Abstract]
Unpaid Principal Balance, With no related allowance recorded	$ 7,897	$ 8,356
Unpaid Principal Balance, With related allowance recorded	13,486	3,000
Unpaid Principal Balance	21,383	11,356
Recorded Investment [Abstract]
Recorded Investment, With no related allowance recorded	7,897	8,356
Recorded Investment, With related allowance recorded	13,486	3,000
Recorded Investment, With related allowance recorded	21,383	11,356
Related Allowance [Abstract]
Related Allowance	1,268	493
Average Recorded Investment [Abstract]
Average Recorded Investment, With no related allowance recorded	5,692	8,202
Average Recorded Investment, With related allowance recorded	6,128	1,348
Average Recorded Investment, With related allowance recorded	11,820	9,550
Commercial and industrial
Unpaid Principal Balance [Abstract]
Unpaid Principal Balance, With no related allowance recorded	302	837
Unpaid Principal Balance, With related allowance recorded		185
Recorded Investment [Abstract]
Recorded Investment, With no related allowance recorded	302	837
Recorded Investment, With related allowance recorded		185
Related Allowance [Abstract]
Related Allowance		64
Average Recorded Investment [Abstract]
Average Recorded Investment, With no related allowance recorded	239	842
Average Recorded Investment, With related allowance recorded	61	300
Construction and development
Unpaid Principal Balance [Abstract]
Unpaid Principal Balance, With no related allowance recorded	1,325	720
Unpaid Principal Balance, With related allowance recorded		530
Recorded Investment [Abstract]
Recorded Investment, With no related allowance recorded	1,325	720
Recorded Investment, With related allowance recorded		530
Related Allowance [Abstract]
Related Allowance		4
Average Recorded Investment [Abstract]
Average Recorded Investment, With no related allowance recorded	938	518
Average Recorded Investment, With related allowance recorded		44
Commercial real estate
Unpaid Principal Balance [Abstract]
Unpaid Principal Balance, With no related allowance recorded	3,923	5,168
Unpaid Principal Balance, With related allowance recorded	13,299	1,985
Recorded Investment [Abstract]
Recorded Investment, With no related allowance recorded	3,923	5,168
Recorded Investment, With related allowance recorded	13,299	1,985
Related Allowance [Abstract]
Related Allowance	1,186	341
Average Recorded Investment [Abstract]
Average Recorded Investment, With no related allowance recorded	3,115	5,138
Average Recorded Investment, With related allowance recorded	5,892	677
Farmland
Unpaid Principal Balance [Abstract]
Unpaid Principal Balance, With related allowance recorded	133	140
Recorded Investment [Abstract]
Recorded Investment, With related allowance recorded	133	140
Related Allowance [Abstract]
Related Allowance	62	78
Average Recorded Investment [Abstract]
Average Recorded Investment, With no related allowance recorded		62
Average Recorded Investment, With related allowance recorded	102	147
1-4 family residential
Unpaid Principal Balance [Abstract]
Unpaid Principal Balance, With no related allowance recorded	2,283	1,223
Unpaid Principal Balance, With related allowance recorded	54	160
Recorded Investment [Abstract]
Recorded Investment, With no related allowance recorded	2,283	1,223
Recorded Investment, With related allowance recorded	54	160
Related Allowance [Abstract]
Related Allowance	20	6
Average Recorded Investment [Abstract]
Average Recorded Investment, With no related allowance recorded	1,225	1,132
Average Recorded Investment, With related allowance recorded	73	128
Multi-family residential
Average Recorded Investment [Abstract]
Average Recorded Investment, With no related allowance recorded		54
Agricultural
Unpaid Principal Balance [Abstract]
Unpaid Principal Balance, With no related allowance recorded	64	408
Recorded Investment [Abstract]
Recorded Investment, With no related allowance recorded	64	408
Average Recorded Investment [Abstract]
Average Recorded Investment, With no related allowance recorded	$ 175	456
Average Recorded Investment, With related allowance recorded		$ 52

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