LOANS AND SERVICING - Summary of loans (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Summary of loans:
Loans receivable	$ 273,870	$ 256,014
Total loans (as a percent)	100.00%	100.00%
Other items:
Net deferred loan costs	$ 479	$ 377
Allowance for loan losses	(2,551)	(2,408)	$ (2,346)	$ (2,229)
Total loans, net	271,798	253,983
Residential loans:
Summary of loans:
Loans receivable	$ 105,140	$ 104,735
Total loans (as a percent)	38.39%	40.91%
One- to four- family, residential loans
Summary of loans:
Loans receivable	$ 89,206	$ 86,472
Total loans (as a percent)	32.57%	33.78%
Other items:
Allowance for loan losses	$ (169)	$ (197)	(201)	(273)
Home equity loans and lines of credit
Summary of loans:
Loans receivable	$ 15,934	$ 18,263
Total loans (as a percent)	5.82%	7.13%
Other items:
Allowance for loan losses	$ (239)	$ (276)	(280)	(249)
Commercial loans:
Summary of loans:
Loans receivable	$ 143,744	$ 130,664
Total loans (as a percent)	52.49%	51.04%
One-to-four family investment property
Summary of loans:
Loans receivable	$ 13,708	$ 15,255
Total loans (as a percent)	5.01%	5.96%
Other items:
Allowance for loan losses	$ (82)	$ (90)	(73)	(46)
Multi-family real estate
Summary of loans:
Loans receivable	$ 28,026	$ 30,709
Total loans (as a percent)	10.23%	12.00%
Other items:
Allowance for loan losses	$ (213)	$ (233)	(175)	(113)
Commercial real estate
Summary of loans:
Loans receivable	$ 81,691	$ 67,152
Total loans (as a percent)	29.83%	26.23%
Other items:
Allowance for loan losses	$ (1,234)	$ (1,021)	(1,008)	(943)
Commercial business loan
Summary of loans:
Loans receivable	$ 20,319	$ 17,548
Total loans (as a percent)	7.42%	6.85%
Other items:
Allowance for loan losses	$ (357)	$ (305)	(328)	(311)
Construction loans
Summary of loans:
Loans receivable	$ 24,783	$ 20,378
Total loans (as a percent)	9.05%	7.96%
One-to-four family, construction loans
Summary of loans:
Loans receivable	$ 13,459	$ 12,967
Total loans (as a percent)	4.91%	5.07%
Other items:
Allowance for loan losses	$ (114)	$ (113)	(129)	(117)
Multi-family
Summary of loans:
Loans receivable	$ 4,696	$ 1,486
Total loans (as a percent)	1.72%	0.58%
Other items:
Allowance for loan losses	$ (39)	$ (12)	(66)	(97)
Non-residential
Summary of loans:
Loans receivable	$ 6,628	$ 5,925
Total loans (as a percent)	2.42%	2.31%
Other items:
Allowance for loan losses	$ (102)	$ (91)	(84)	(77)
Consumer
Summary of loans:
Loans receivable	$ 203	$ 237
Total loans (as a percent)	0.07%	0.09%
Other items:
Allowance for loan losses	$ (2)	$ (2)	$ (2)	$ (3)