LOANS RECEIVABLE - Summary of past due loans in non-accrual and past 90 days still on accrual (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2023	Dec. 31, 2022
Financing Receivable, Past Due [Line Items]
Non-accrual	$ 7,857	$ 7,767
Interest Income Recognized on Non-accrual Loans	0
Amortized Cost Basis of Loans >= 90 Day Past Due and Still Accruing	0	61
Amortized Cost Basis of Non-accrual Loans Without Related Allowance	7,857
Residential Portfolio Segment \| Residential one-to-four family
Financing Receivable, Past Due [Line Items]
Non-accrual	7,572	7,498
Interest Income Recognized on Non-accrual Loans	0
Amortized Cost Basis of Loans >= 90 Day Past Due and Still Accruing	0	0
Amortized Cost Basis of Non-accrual Loans Without Related Allowance	7,572
Residential Portfolio Segment \| Multifamily
Financing Receivable, Past Due [Line Items]
Non-accrual	168	182
Interest Income Recognized on Non-accrual Loans	0
Amortized Cost Basis of Loans >= 90 Day Past Due and Still Accruing	0	0
Amortized Cost Basis of Non-accrual Loans Without Related Allowance	168
Nonresidential Portfolio Segment \| Non-residential
Financing Receivable, Past Due [Line Items]
Non-accrual	0	0
Interest Income Recognized on Non-accrual Loans	0
Amortized Cost Basis of Loans >= 90 Day Past Due and Still Accruing	0	0
Amortized Cost Basis of Non-accrual Loans Without Related Allowance	0
Construction and Land Portfolio Segment \| Construction
Financing Receivable, Past Due [Line Items]
Non-accrual	0	0
Interest Income Recognized on Non-accrual Loans	0
Amortized Cost Basis of Loans >= 90 Day Past Due and Still Accruing	0	0
Amortized Cost Basis of Non-accrual Loans Without Related Allowance	0
Junior Lien Portfolio Segment \| Junior liens
Financing Receivable, Past Due [Line Items]
Non-accrual	52	52
Interest Income Recognized on Non-accrual Loans	0
Amortized Cost Basis of Loans >= 90 Day Past Due and Still Accruing	0	0
Amortized Cost Basis of Non-accrual Loans Without Related Allowance	52
Commercial Portfolio Segment \| Commercial and industrial (including PPP)
Financing Receivable, Past Due [Line Items]
Non-accrual	65	35
Interest Income Recognized on Non-accrual Loans	0
Amortized Cost Basis of Loans >= 90 Day Past Due and Still Accruing	0	$ 61
Amortized Cost Basis of Non-accrual Loans Without Related Allowance	$ 65

Amortized cost excluding accrued interest, of financing receivable 90 days or more past due and still accruing. Excludes net investment in lease.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919258-210447

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- Definition

Amortized cost excluding accrued interest, of financing receivable on nonaccrual status. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919258-210447

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- Definition

Amortized cost excluding accrued interest, of financing receivable on nonaccrual status with no allowance for credit loss. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919258-210447

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- Definition

Amount of interest income on financing receivable on nonaccrual status.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919258-210447

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