Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Mar. 31, 2020
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	$ 4,916	$ 4,625	$ 4,946	$ 4,646
Charge-offs	(57)	(33)	(76)	(162)
Recoveries	275	7	367	107
Provision for loan losses	4	8	(99)	16
Allowance for loan losses - Ending Balance	5,138	4,607	5,138	4,607
Allowance for Loan Losses, Collectively Evaluated for Impairment	4,964		4,964		$ 4,780
Allowance for Loan Losses, Individually Evaluated for Impairment	174		174		166
Loans, gross	468,593		468,593		428,732
Loans Receivable, Collectively Evaluated for Impairment	455,291		455,291		420,282
Loans Receivable, Individually Evaluated for Impairment	13,302		13,302		8,450
One-to-four family
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	953	1,289	1,055	1,274
Charge-offs	0	(12)	0	(12)
Recoveries	1	0	88	8
Provision for loan losses	(90)	(96)	(279)	(89)
Allowance for loan losses - Ending Balance	864	1,181	864	1,181
Allowance for Loan Losses, Collectively Evaluated for Impairment	831		831		899
Allowance for Loan Losses, Individually Evaluated for Impairment	33		33		156
Loans, gross	83,047		83,047		107,528
Loans Receivable, Collectively Evaluated for Impairment	79,208		79,208		102,902
Loans Receivable, Individually Evaluated for Impairment	3,839		3,839		4,626
Multifamily
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	960	884	1,011	885
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for loan losses	67	36	16	35
Allowance for loan losses - Ending Balance	1,027	920	1,027	920
Allowance for Loan Losses, Collectively Evaluated for Impairment	1,027		1,027		1,011
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0		0
Loans, gross	107,723		107,723		89,887
Loans Receivable, Collectively Evaluated for Impairment	107,353		107,353		89,512
Loans Receivable, Individually Evaluated for Impairment	370		370		375
Commercial real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	969	695	812	766
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for loan losses	(3)	(4)	154	(75)
Allowance for loan losses - Ending Balance	966	691	966	691
Allowance for Loan Losses, Collectively Evaluated for Impairment	966		966		812
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0		0
Loans, gross	147,520		147,520		142,410
Loans Receivable, Collectively Evaluated for Impairment	146,360		146,360		142,410
Loans Receivable, Individually Evaluated for Impairment	1,160		1,160		0
Business
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	1,636	1,491	1,567	1,330
Charge-offs	(5)	(13)	(24)	(69)
Recoveries	273	7	275	97
Provision for loan losses	(66)	(1)	20	126
Allowance for loan losses - Ending Balance	1,838	1,484	1,838	1,484
Allowance for Loan Losses, Collectively Evaluated for Impairment	1,697		1,697		1,557
Allowance for Loan Losses, Individually Evaluated for Impairment	141		141		10
Loans, gross	127,548		127,548		85,659
Loans Receivable, Collectively Evaluated for Impairment	119,615		119,615		82,210
Loans Receivable, Individually Evaluated for Impairment	7,933		7,933		3,449
Consumer
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	189	248	212	154
Charge-offs	(52)	(8)	(52)	(81)
Recoveries	1	0	4	2
Provision for loan losses	52	(9)	26	156
Allowance for loan losses - Ending Balance	190	231	190	231
Allowance for Loan Losses, Collectively Evaluated for Impairment	190		190		212
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0		0
Loans, gross	2,755		2,755		3,248
Loans Receivable, Collectively Evaluated for Impairment	2,755		2,755		3,248
Loans Receivable, Individually Evaluated for Impairment	0		0		0
Unallocated
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	209	18	289	237
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for loan losses	44	82	(36)	(137)
Allowance for loan losses - Ending Balance	253	$ 100	253	$ 100
Allowance for Loan Losses, Collectively Evaluated for Impairment	253		253		289
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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The balance of financing receivables that were individually 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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