Past Due Financing Receivables (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Mar. 31, 2023
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	$ 624,651	$ 597,896
Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	16,314	15,140
Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	5,200	211
Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	25,024	7,594
Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	46,538	22,945
Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	578,113	574,951
One-to-four family
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	84,041	65,808
One-to-four family | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	346	1,207
One-to-four family | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	185
One-to-four family | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,991	2,475
One-to-four family | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,337	3,867
One-to-four family | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	80,704	61,941
Multifamily
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	177,772	179,117
Multifamily | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	8,758	1,458
Multifamily | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Multifamily | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,543	71
Multifamily | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	11,301	1,529
Multifamily | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	166,471	177,588
Commercial real estate
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	174,202	178,424
Commercial real estate | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,533	1,370
Commercial real estate | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,945	0
Commercial real estate | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	5,937	0
Commercial real estate | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	12,415	1,370
Commercial real estate | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	161,787	177,054
Construction
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,559	0
Construction | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Construction | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Construction | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Construction | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0
Construction | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,559
Business
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	172,204	166,908	[1]
Business | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,535	11,006
Business | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,137	0
Business | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	13,535	5,014
Business | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	19,207	16,020
Business | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	152,997	150,888
Consumer
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income	14,873	7,639	[2]
Consumer | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	142	99
Consumer | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	118	26
Consumer | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	18	34
Consumer | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	278	159
Consumer | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 14,595	$ 7,480

[1] (1) Includes PPP loans and business overdrafts

[2] 2) Includes personal loans and consumer overdrafts