LOANS RECEIVABLE - Credit quality indicators (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Financing Receivable, Credit Quality Indicator [Line Items]
2023	$ 71,005
2022	523,008
2021	313,307
2020	67,018
2019	86,578
Pre-2019	520,814
Revolving Loans	15
Total	1,581,745	$ 1,545,127
Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total		1,534,434
Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total		2,224
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total		8,469
Doubtful / Loss
Financing Receivable, Credit Quality Indicator [Line Items]
Total		0
Residential one-to-four family
Financing Receivable, Credit Quality Indicator [Line Items]
Total		597,254
Multifamily
Financing Receivable, Credit Quality Indicator [Line Items]
Total		690,690
Non-residential
Financing Receivable, Credit Quality Indicator [Line Items]
Total		216,061
Construction
Financing Receivable, Credit Quality Indicator [Line Items]
Total		17,799
Junior liens
Financing Receivable, Credit Quality Indicator [Line Items]
Total		18,631
Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Total		4,653
Consumer and other
Financing Receivable, Credit Quality Indicator [Line Items]
Total		39
Residential Portfolio Segment | Residential one-to-four family
Financing Receivable, Credit Quality Indicator [Line Items]
2023	10,036
2022	100,456
2021	119,000
2020	15,343
2019	19,279
Pre-2019	316,282
Revolving Loans	0
Total	580,396	597,254
Residential Portfolio Segment | Residential one-to-four family | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2023	10,036
2022	100,456
2021	119,000
2020	15,343
2019	19,279
Pre-2019	308,798
Revolving Loans	0
Total	572,912	589,137
Residential Portfolio Segment | Residential one-to-four family | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total		247
Residential Portfolio Segment | Residential one-to-four family | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	0
Pre-2019	7,484
Revolving Loans	0
Total	7,484	7,870
Residential Portfolio Segment | Residential one-to-four family | Doubtful / Loss
Financing Receivable, Credit Quality Indicator [Line Items]
Total		0
Residential Portfolio Segment | Multifamily
Financing Receivable, Credit Quality Indicator [Line Items]
2023	17,240
2022	282,553
2021	161,025
2020	35,832
2019	59,947
Pre-2019	140,359
Revolving Loans	0
Total	696,956	690,690
Residential Portfolio Segment | Multifamily | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2023	17,240
2022	282,553
2021	161,025
2020	35,832
2019	59,947
Pre-2019	139,869
Revolving Loans	0
Total	696,466	689,277
Residential Portfolio Segment | Multifamily | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	0
Pre-2019	330
Revolving Loans	0
Total	330	897
Residential Portfolio Segment | Multifamily | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	0
Pre-2019	160
Revolving Loans	0
Total	160	516
Residential Portfolio Segment | Multifamily | Doubtful / Loss
Financing Receivable, Credit Quality Indicator [Line Items]
Total		0
Nonresidential Portfolio Segment | Non-residential
Financing Receivable, Credit Quality Indicator [Line Items]
2023	25,820
2022	120,496
2021	14,929
2020	15,310
2019	5,481
Pre-2019	55,211
Revolving Loans	0
Total	237,247	216,061
Nonresidential Portfolio Segment | Non-residential | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2023	25,820
2022	120,496
2021	14,929
2020	15,310
2019	5,481
Pre-2019	54,175
Revolving Loans	0
Total	236,211	214,981
Nonresidential Portfolio Segment | Non-residential | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	0
Pre-2019	1,036
Revolving Loans	0
Total	1,036	1,080
Nonresidential Portfolio Segment | Non-residential | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total		0
Nonresidential Portfolio Segment | Non-residential | Doubtful / Loss
Financing Receivable, Credit Quality Indicator [Line Items]
Total		0
Construction and Land Portfolio Segment | Construction
Financing Receivable, Credit Quality Indicator [Line Items]
2023	8,291
2022	13,972
2021	13,654
2020	0
2019	0
Pre-2019	115
Revolving Loans	0
Total	36,032	17,799
Construction and Land Portfolio Segment | Construction | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2023	8,291
2022	13,972
2021	13,654
2020	0
2019	0
Pre-2019	115
Revolving Loans	0
Total	36,032	17,799
Construction and Land Portfolio Segment | Construction | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total		0
Construction and Land Portfolio Segment | Construction | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total		0
Construction and Land Portfolio Segment | Construction | Doubtful / Loss
Financing Receivable, Credit Quality Indicator [Line Items]
Total		0
Junior Lien Portfolio Segment | Junior liens
Financing Receivable, Credit Quality Indicator [Line Items]
2023	3,311
2022	5,421
2021	1,525
2020	363
2019	1,871
Pre-2019	8,847
Revolving Loans	0
Total	21,338	18,631
Junior Lien Portfolio Segment | Junior liens | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2023	3,311
2022	5,421
2021	1,525
2020	363
2019	1,871
Pre-2019	8,796
Revolving Loans	0
Total	21,287	18,579
Junior Lien Portfolio Segment | Junior liens | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total		0
Junior Lien Portfolio Segment | Junior liens | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	0
Pre-2019	51
Revolving Loans	0
Total	51	52
Junior Lien Portfolio Segment | Junior liens | Doubtful / Loss
Financing Receivable, Credit Quality Indicator [Line Items]
Total		0
Commercial Portfolio Segment | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
2023	6,289
2022	110
2021	3,174
2020	170
2019	0
Pre-2019	0
Revolving Loans	0
Total	9,743	4,653
Commercial Portfolio Segment | Commercial and industrial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2023	6,289
2022	110
2021	3,109
2020	170
2019	0
Pre-2019	0
Revolving Loans	0
Total	9,678	4,653
Commercial Portfolio Segment | Commercial and industrial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total		0
Commercial Portfolio Segment | Commercial and industrial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0
2022	0
2021	65
2020	0
2019	0
Pre-2019	0
Revolving Loans	0
Total	65	0
Commercial Portfolio Segment | Commercial and industrial | Doubtful / Loss
Financing Receivable, Credit Quality Indicator [Line Items]
Total		0
Consumer and Other Portfolio Segment | Consumer and other
Financing Receivable, Credit Quality Indicator [Line Items]
2023	18
2022	0
2021	0
2020	0
2019	0
Pre-2019	0
Revolving Loans	15
Total	33	39
Consumer and Other Portfolio Segment | Consumer and other | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2023	18
2022	0
2021	0
2020	0
2019	0
Pre-2019	0
Revolving Loans	15
Total	$ 33	8
Consumer and Other Portfolio Segment | Consumer and other | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total		0
Consumer and Other Portfolio Segment | Consumer and other | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total		31
Consumer and Other Portfolio Segment | Consumer and other | Doubtful / Loss
Financing Receivable, Credit Quality Indicator [Line Items]
Total		$ 0