LOANS AND ALLOWANCE FOR CREDIT LOSSES - Impaired Financing Receivables (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2020	Mar. 31, 2021
Loans Receivable
Impaired Financing Receivable, Recorded Investment	$ 10,802	$ 9,048
Impaired Financing Receivable, Unpaid Principal Balance	12,226	10,109	$ 10,902
Impaired Financing Receivable, Related Allowance	890	713	2,057
Impaired Financing Receivable, Average Recorded Investment	10,529	9,739
Impaired Financing Receivable Interest Income Recognized	148	533
Commercial Real Estate
Impaired Financing Receivable, Recorded Investment	4,109	3,438
Impaired Financing Receivable, Unpaid Principal Balance	4,143	3,472
Impaired Financing Receivable, Related Allowance	506	445
Impaired Financing Receivable, Average Recorded Investment	4,122	3,736
Impaired Financing Receivable Interest Income Recognized	30	135
Commercial Real Estate | Loans Receivable
Impaired Financing Receivable, Unpaid Principal Balance			5,752
Impaired Financing Receivable, Related Allowance			1,617
Consumer auto
Impaired Financing Receivable, Recorded Investment	1,030	865
Impaired Financing Receivable, Unpaid Principal Balance	1,253	964
Impaired Financing Receivable, Related Allowance	167	140
Impaired Financing Receivable, Average Recorded Investment	1,078	932
Impaired Financing Receivable Interest Income Recognized	26	91
Home Equity Line of Credit
Impaired Financing Receivable, Recorded Investment	475	630
Impaired Financing Receivable, Unpaid Principal Balance	499	668
Impaired Financing Receivable, Related Allowance	4	5
Impaired Financing Receivable, Average Recorded Investment	577	550
Impaired Financing Receivable Interest Income Recognized	12	36
Home Equity Line of Credit | Loans Receivable
Impaired Financing Receivable, Unpaid Principal Balance			393
Land development | Loans Receivable
Impaired Financing Receivable, Unpaid Principal Balance			622
Impaired Financing Receivable, Related Allowance			367
Subdivision construction
Impaired Financing Receivable, Recorded Investment	246	20
Impaired Financing Receivable, Unpaid Principal Balance	246	20
Impaired Financing Receivable, Related Allowance	93
Impaired Financing Receivable, Average Recorded Investment	247	115
Impaired Financing Receivable Interest Income Recognized	2	3
Owner occupied one- to four-family residential
Impaired Financing Receivable, Recorded Investment	2,929	3,457
Impaired Financing Receivable, Unpaid Principal Balance	3,214	3,776
Impaired Financing Receivable, Related Allowance	79	90
Impaired Financing Receivable, Average Recorded Investment	2,522	2,999
Impaired Financing Receivable Interest Income Recognized	46	169
Owner occupied one- to four-family residential | Loans Receivable
Impaired Financing Receivable, Unpaid Principal Balance			3,950
Impaired Financing Receivable, Related Allowance			73
Non-owner occupied one- to four-family residential
Impaired Financing Receivable, Recorded Investment	494	69
Impaired Financing Receivable, Unpaid Principal Balance	694	106
Impaired Financing Receivable, Related Allowance	18
Impaired Financing Receivable, Average Recorded Investment	433	309
Impaired Financing Receivable Interest Income Recognized	6	18
Other residential | Loans Receivable
Impaired Financing Receivable, Unpaid Principal Balance			$ 185
Commercial business
Impaired Financing Receivable, Recorded Investment	1,238	166
Impaired Financing Receivable, Unpaid Principal Balance	1,736	551
Impaired Financing Receivable, Related Allowance	10	14
Impaired Financing Receivable, Average Recorded Investment	1,263	800
Impaired Financing Receivable Interest Income Recognized	16	34
Consumer
Impaired Financing Receivable, Recorded Investment	281	403
Impaired Financing Receivable, Unpaid Principal Balance	441	552
Impaired Financing Receivable, Related Allowance	13	19
Impaired Financing Receivable, Average Recorded Investment	287	298
Impaired Financing Receivable Interest Income Recognized	$ 10	$ 47