Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Mar. 31, 2021
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	$ 5,214	$ 4,836	$ 5,140	$ 4,946
Charge-offs	(44)	(9)	(99)	(19)
Recoveries	141	90	198	92
Provision for loan losses	204	(1)	276	(103)
Allowance for loan losses - Ending Balance	5,515	4,916	5,515	4,916
Allowance for Loan Losses, Collectively Evaluated for Impairment	5,387		5,387		$ 4,982
Allowance for Loan Losses, Individually Evaluated for Impairment	128		128		158
Loans, gross	520,653		520,653		483,549
Loans Receivable, Collectively Evaluated for Impairment	508,283		508,283		470,681
Loans Receivable, Individually Evaluated for Impairment	12,370		12,370		12,868
One-to-four family
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	1,086	972	1,058	1,055
Charge-offs	0	0	0	0
Recoveries	0	87	0	87
Provision for loan losses	(71)	(106)	(43)	(189)
Allowance for loan losses - Ending Balance	1,015	953	1,015	953
Allowance for Loan Losses, Collectively Evaluated for Impairment	985		985		1,026
Allowance for Loan Losses, Individually Evaluated for Impairment	30		30		32
Loans, gross	75,202		75,202		78,213
Loans Receivable, Collectively Evaluated for Impairment	71,407		71,407		74,387
Loans Receivable, Individually Evaluated for Impairment	3,795		3,795		3,826
Multifamily
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	826	911	880	1,011
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for loan losses	88	49	34	(51)
Allowance for loan losses - Ending Balance	914	960	914	960
Allowance for Loan Losses, Collectively Evaluated for Impairment	914		914		880
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0		0
Loans, gross	129,589		129,589		106,400
Loans Receivable, Collectively Evaluated for Impairment	128,707		128,707		106,031
Loans Receivable, Individually Evaluated for Impairment	882		882		369
Commercial real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	870	955	907	812
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for loan losses	132	14	95	157
Allowance for loan losses - Ending Balance	1,002	969	1,002	969
Allowance for Loan Losses, Collectively Evaluated for Impairment	1,002		1,002		907
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0		0
Loans, gross	156,197		156,197		148,809
Loans Receivable, Collectively Evaluated for Impairment	156,005		156,005		147,891
Loans Receivable, Individually Evaluated for Impairment	192		192		918
Business
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	2,104	1,511	1,855	1,567
Charge-offs	0	(9)	0	(19)
Recoveries	1	2	50	2
Provision for loan losses	1	132	201	86
Allowance for loan losses - Ending Balance	2,106	1,636	2,106	1,636
Allowance for Loan Losses, Collectively Evaluated for Impairment	2,008		2,008		1,729
Allowance for Loan Losses, Individually Evaluated for Impairment	98		98		126
Loans, gross	157,627		157,627		147,680
Loans Receivable, Collectively Evaluated for Impairment	150,126		150,126		139,925
Loans Receivable, Individually Evaluated for Impairment	7,501		7,501		7,755
Consumer
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	144	202	165	212
Charge-offs	(44)	0	(99)	0
Recoveries	12	1	20	3
Provision for loan losses	25	(14)	51	(26)
Allowance for loan losses - Ending Balance	137	189	137	189
Allowance for Loan Losses, Collectively Evaluated for Impairment	137		137		165
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0		0
Loans, gross	2,038		2,038		2,447
Loans Receivable, Collectively Evaluated for Impairment	2,038		2,038		2,447
Loans Receivable, Individually Evaluated for Impairment	0		0		0
Unallocated
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	184	285	275	289
Charge-offs	0	0	0	0
Recoveries	128	0	128	0
Provision for loan losses	29	(76)	(62)	(80)
Allowance for loan losses - Ending Balance	341	$ 209	341	$ 209
Allowance for Loan Losses, Collectively Evaluated for Impairment	341		341		275
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0		0
Loans, gross	0		0		0
Loans Receivable, Collectively Evaluated for Impairment	0		0		0
Loans Receivable, Individually Evaluated for Impairment	$ 0		$ 0		$ 0

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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The balance of financing receivables that were collectively evaluated for impairment.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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Amount of expense related to estimated loss from loan and lease transactions.

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