ALLOWANCE FOR LOAN LOSSES, Impaired Real Estate Loans (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Unpaid Principal Balance [Abstract]
With related allowance recorded		$ 0		$ 0		$ 309
Total		6,002		6,002		5,999
Recorded Investment [Abstract]
With related allowance recorded	[1]	0		0		309
Total	[1]	6,002		6,002		5,999
Related Allowance [Abstract]
Related allowance		0		0		230
Average Recorded Investment [Abstract]
Total	[1]	7,524	$ 7,659	7,016	$ 7,841
Interest Income Recognized [Abstract]
Total		100	101	217	189
Real Estate Loans [Member]
Unpaid Principal Balance [Abstract]
With no related allowance recorded		6,002		6,002		5,690
Recorded Investment [Abstract]
With no related allowance recorded	[1]	6,002		6,002		5,690
Related Allowance [Abstract]
Related allowance		0		0		0
Average Recorded Investment [Abstract]
With no related allowance recorded	[1]	7,408	7,070	6,835	7,448
Interest Income Recognized [Abstract]
With no related allowance recorded		100	101	211	189
Real Estate Loans [Member] | One-to-Four Family Residential, Including Condominium and Cooperative Apartment [Member]
Unpaid Principal Balance [Abstract]
With no related allowance recorded		11		11		14
Recorded Investment [Abstract]
With no related allowance recorded	[1]	11		11		14
Related Allowance [Abstract]
Related allowance		0		0		0
Average Recorded Investment [Abstract]
With no related allowance recorded	[1]	11	19	12	20
Interest Income Recognized [Abstract]
With no related allowance recorded		0	0	0	0
Real Estate Loans [Member] | Multifamily Residential and Residential Mixed-Use [Member]
Unpaid Principal Balance [Abstract]
With no related allowance recorded		1,099		1,099		551
Recorded Investment [Abstract]
With no related allowance recorded	[1]	1,099		1,099		551
Related Allowance [Abstract]
Related allowance		0		0		0
Average Recorded Investment [Abstract]
With no related allowance recorded	[1]	608	601	589	607
Interest Income Recognized [Abstract]
With no related allowance recorded		9	8	22	20
Real Estate Loans [Member] | Commercial Real Estate and Commercial Mixed-Use [Member]
Unpaid Principal Balance [Abstract]
With no related allowance recorded		4,892		4,892		5,125
Recorded Investment [Abstract]
With no related allowance recorded	[1]	4,892		4,892		5,125
Related Allowance [Abstract]
Related allowance		0		0		0
Average Recorded Investment [Abstract]
With no related allowance recorded	[1]	6,789	6,450	6,234	6,821
Interest Income Recognized [Abstract]
With no related allowance recorded		91	93	189	169
C&I [Member]
Unpaid Principal Balance [Abstract]
With related allowance recorded		0		0		309
Recorded Investment [Abstract]
With related allowance recorded	[1]	0		0		309
Related Allowance [Abstract]
Related allowance		0		0		$ 230
Average Recorded Investment [Abstract]
With an allowance recorded	[1]	116	589	181	393
Interest Income Recognized [Abstract]
With an allowance recorded		$ 0	$ 0	$ 6	$ 0

[1] The recorded investment excludes accrued interest receivable and deferred costs due to immateriality.