LOANS AND SERVICING - Past-due and non-accrual loans (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Past-due and non-accrual loans
Past due loans	$ 1,017	$ 938
Total Current	278,475	255,076
Total Loans	279,492	256,014
Non-accrual Loans	953	776
Loans delinquent for: 30 - 59 Days
Past-due and non-accrual loans
Past due loans	198
Loans delinquent for: 60 - 89 Days
Past-due and non-accrual loans
Past due loans	23
Loans delinquent for: 90 days or more
Past-due and non-accrual loans
Past due loans	796
Residential loans:
Past-due and non-accrual loans
Total Loans	106,069	104,735
One- to four- family, residential loans
Past-due and non-accrual loans
Past due loans	755	649
Total Current	89,435	85,823
Total Loans	90,190	86,472
Non-accrual Loans	755	776
One- to four- family, residential loans | Loans delinquent for: 90 days or more
Past-due and non-accrual loans
Past due loans	755	649
Home equity loans and lines of credit
Past-due and non-accrual loans
Past due loans	252	273
Total Current	15,627	17,990
Total Loans	15,879	18,263
Non-accrual Loans	198
Home equity loans and lines of credit | Loans delinquent for: 30 - 59 Days
Past-due and non-accrual loans
Past due loans	191	273
Home equity loans and lines of credit | Loans delinquent for: 60 - 89 Days
Past-due and non-accrual loans
Past due loans	20
Home equity loans and lines of credit | Loans delinquent for: 90 days or more
Past-due and non-accrual loans
Past due loans	41
Commercial loans:
Past-due and non-accrual loans
Total Loans	148,087	130,664
One-to-four family investment property
Past-due and non-accrual loans
Total Current	13,081	15,255
Total Loans	13,081	15,255
Multi-family real estate
Past-due and non-accrual loans
Total Current	30,748	30,709
Total Loans	30,748	30,709
Commercial real estate
Past-due and non-accrual loans
Total Current	83,583	67,152
Total Loans	83,583	67,152
Commercial business loan
Past-due and non-accrual loans
Past due loans		12
Total Current	20,675	17,536
Total Loans	20,675	17,548
Commercial business loan | Loans delinquent for: 30 - 59 Days
Past-due and non-accrual loans
Past due loans		12
Construction loans
Past-due and non-accrual loans
Total Loans	25,154	20,378
One-to-four family, construction loans
Past-due and non-accrual loans
Total Current	12,599	12,967
Total Loans	12,599	12,967
Multi-family
Past-due and non-accrual loans
Total Current	5,725	1,486
Total Loans	5,725	1,486
Non-residential
Past-due and non-accrual loans
Total Current	6,830	5,925
Total Loans	6,830	5,925
Consumer
Past-due and non-accrual loans
Past due loans	10	4
Total Current	172	233
Total Loans	182	237
Consumer | Loans delinquent for: 30 - 59 Days
Past-due and non-accrual loans
Past due loans	7
Consumer | Loans delinquent for: 60 - 89 Days
Past-due and non-accrual loans
Past due loans	$ 3	$ 4