Credit Quality Indicators (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Mar. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross	$ 552,877	$ 483,549
Multifamily
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross	154,230	106,400
Multifamily | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross	148,139	101,212
Multifamily | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross	0	0
Multifamily | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross	6,091	5,188
Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross	166,050	148,809
Commercial real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross	156,636	142,168
Commercial real estate | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross	8,206	5,531
Commercial real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross	1,208	1,110
Business
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross	158,487	147,680
Business | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross	142,693	137,447
Business | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross	5,949	1,585
Business | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross	9,845	8,648
One-to-four family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross	72,375	78,213
One-to-four family | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross	67,457	74,689
One-to-four family | Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross	4,918	3,524
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross	1,735	2,447
Consumer | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross	1,678	2,356
Consumer | Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross	$ 57	$ 91