LOANS - Composition of the Company's loan portfolio (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 15, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 1,032,089	$ 987,779	$ 983,931
Less deferred loan origination fees, net	(2,114)	(1,739)
Total loans	1,029,975	986,040		$ 198,440
Allowance for loan losses	(8,324)	(8,669)		$ 0
Total loans, net	$ 1,021,651	$ 977,371
Less deferred loan origination fees, net	(0.18%)	(0.18%)
Percent of total	100.00%	100.00%
1-to-4 family residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 151,697	$ 159,597	156,901
Total loans	$ 151,697	$ 159,597
Percent of total	14.73%	16.19%
Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 459,115	$ 457,611	403,100
Total loans	$ 459,115	$ 457,611
Percent of total	44.58%	46.41%
Multi-family residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 69,124	$ 63,459	76,983
Total loans	$ 69,124	$ 63,459
Percent of total	6.71%	6.44%
Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 221,878	$ 170,404	177,933
Total loans	$ 221,878	$ 170,404
Percent of total	21.55%	17.28%
HELOC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 44,514	$ 49,713	52,606
Total loans	$ 44,514	$ 49,713
Percent of total	4.32%	5.04%
Total real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 946,328	$ 900,784
Percent of total	91.89%	91.36%
Commercial and industrial Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 75,748	$ 74,181	$ 106,164
Total loans	$ 75,748	$ 74,181
Percent of total	7.35%	7.52%
Loans to individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 9,779	$ 12,597
Percent of total	0.95%	1.28%
Overdrafts [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 234	$ 217
Percent of total	0.02%	0.02%
Total other loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 85,761	$ 86,995
Percent of total	8.32%	8.82%