Loans Receivable, Net - Credit Quality Indicators (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Mar. 31, 2022
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	$ 597,896	$ 579,504
Multifamily
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	179,117	162,261
Multifamily | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	175,981	155,274
Multifamily | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	771	897
Multifamily | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	2,365	6,090
Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	178,424	175,313
Commercial real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	170,534	164,543
Commercial real estate | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	701	8,157
Commercial real estate | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	7,189	2,613
Business
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	166,908	170,031
Business | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	154,056	155,196
Business | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	5,719	6,302
Business | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	7,133	8,533
One-to-four family
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	65,808	70,261
One-to-four family | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	60,629	65,369
One-to-four family | Non-performing
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	5,179	4,892
Consumer
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	7,639	1,638
Consumer | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	7,639	1,613
Consumer | Non-performing
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	$ 0	$ 25