Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Mar. 31, 2020
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	$ 4,836	$ 4,670	$ 4,946	$ 4,646
Charge-offs	(9)	(62)	(19)	(129)
Recoveries	90	10	92	100
Provision for loan losses	(1)	7	(103)	8
Allowance for loan losses - Ending Balance	4,916	4,625	4,916	4,625
Allowance for Loan Losses, Collectively Evaluated for Impairment	4,873		4,873		$ 4,780
Allowance for Loan Losses, Individually Evaluated for Impairment	43		43		166
Loans, gross	464,199		464,199		428,732
Loans Receivable, Collectively Evaluated for Impairment	455,845		455,845		420,282
Loans Receivable, Individually Evaluated for Impairment	8,354		8,354		8,450
One-to-four family
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	972	1,232	1,055	1,274
Charge-offs	0	0	0	0
Recoveries	87	8	87	8
Provision for loan losses	(106)	49	(189)	7
Allowance for loan losses - Ending Balance	953	1,289	953	1,289
Allowance for Loan Losses, Collectively Evaluated for Impairment	920		920		899
Allowance for Loan Losses, Individually Evaluated for Impairment	33		33		156
Loans, gross	87,569		87,569		107,528
Loans Receivable, Collectively Evaluated for Impairment	83,719		83,719		102,902
Loans Receivable, Individually Evaluated for Impairment	3,850		3,850		4,626
Multifamily
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	911	875	1,011	885
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for loan losses	49	9	(51)	(1)
Allowance for loan losses - Ending Balance	960	884	960	884
Allowance for Loan Losses, Collectively Evaluated for Impairment	960		960		1,011
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0		0
Loans, gross	97,162		97,162		89,887
Loans Receivable, Collectively Evaluated for Impairment	96,790		96,790		89,512
Loans Receivable, Individually Evaluated for Impairment	372		372		375
Commercial real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	955	668	812	766
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for loan losses	14	27	157	(71)
Allowance for loan losses - Ending Balance	969	695	969	695
Allowance for Loan Losses, Collectively Evaluated for Impairment	969		969		812
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0		0
Loans, gross	147,951		147,951		142,410
Loans Receivable, Collectively Evaluated for Impairment	146,791		146,791		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	1,511	1,400	1,567	1,330
Charge-offs	(9)	(56)	(19)	(56)
Recoveries	2	2	2	90
Provision for loan losses	132	145	86	127
Allowance for loan losses - Ending Balance	1,636	1,491	1,636	1,491
Allowance for Loan Losses, Collectively Evaluated for Impairment	1,626		1,626		1,557
Allowance for Loan Losses, Individually Evaluated for Impairment	10		10		10
Loans, gross	128,641		128,641		85,659
Loans Receivable, Collectively Evaluated for Impairment	125,669		125,669		82,210
Loans Receivable, Individually Evaluated for Impairment	2,972		2,972		3,449
Consumer
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	202	240	212	154
Charge-offs	0	(6)	0	(73)
Recoveries	1	0	3	2
Provision for loan losses	(14)	14	(26)	165
Allowance for loan losses - Ending Balance	189	248	189	248
Allowance for Loan Losses, Collectively Evaluated for Impairment	189		189		212
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0		0
Loans, gross	2,876		2,876		3,248
Loans Receivable, Collectively Evaluated for Impairment	2,876		2,876		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	285	255	289	237
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for loan losses	(76)	(237)	(80)	(219)
Allowance for loan losses - Ending Balance	209	$ 18	209	$ 18
Allowance for Loan Losses, Collectively Evaluated for Impairment	209		209		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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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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