Loans Receivable and Allowance for Loan and Lease Losses Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2019
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	$ 4,646	$ 5,126
Charge-offs	(67)	(110)
Recoveries	90	166
Provision for loan losses	1	5
Allowance for loan losses - Ending Balance	4,670	5,187
Allowance for Loan Losses, Collectively Evaluated for Impairment	4,473		$ 4,457
Allowance for Loan Losses, Individually Evaluated for Impairment	197		189
Loans, gross	421,935		428,828
Loans Receivable, Collectively Evaluated for Impairment	410,267		416,459
Loans Receivable, Individually Evaluated for Impairment	11,668		12,369
One-to-four family
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	1,274	1,210
Charge-offs	0	(96)
Recoveries	0	0
Provision for loan losses	(42)	739
Allowance for loan losses - Ending Balance	1,232	1,853
Allowance for Loan Losses, Collectively Evaluated for Impairment	1,052		1,103
Allowance for Loan Losses, Individually Evaluated for Impairment	180		171
Loans, gross	107,558		109,926
Loans Receivable, Collectively Evaluated for Impairment	102,259		104,509
Loans Receivable, Individually Evaluated for Impairment	5,299		5,417
Multifamily
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	885	1,819
Charge-offs	0	0
Recoveries	0	158
Provision for loan losses	(10)	(590)
Allowance for loan losses - Ending Balance	875	1,387
Allowance for Loan Losses, Collectively Evaluated for Impairment	875		885
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0
Loans, gross	85,822		86,886
Loans Receivable, Collectively Evaluated for Impairment	82,678		83,672
Loans Receivable, Individually Evaluated for Impairment	3,144		3,214
Commercial real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	766	1,052
Charge-offs	0	0
Recoveries	0	0
Provision for loan losses	(98)	(512)
Allowance for loan losses - Ending Balance	668	540
Allowance for Loan Losses, Collectively Evaluated for Impairment	668		766
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0
Loans, gross	132,112		131,292
Loans Receivable, Collectively Evaluated for Impairment	132,112		130,816
Loans Receivable, Individually Evaluated for Impairment	0		476
Business
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	1,330	1,003
Charge-offs	0	(11)
Recoveries	88	5
Provision for loan losses	(18)	172
Allowance for loan losses - Ending Balance	1,400	1,169
Allowance for Loan Losses, Collectively Evaluated for Impairment	1,383		1,312
Allowance for Loan Losses, Individually Evaluated for Impairment	17		18
Loans, gross	92,615		96,661
Loans Receivable, Collectively Evaluated for Impairment	89,390		93,399
Loans Receivable, Individually Evaluated for Impairment	3,225		3,262
Consumer
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	154	18
Charge-offs	(67)	(3)
Recoveries	2	3
Provision for loan losses	151	154
Allowance for loan losses - Ending Balance	240	172
Allowance for Loan Losses, Collectively Evaluated for Impairment	240		154
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0
Loans, gross	3,828		4,063
Loans Receivable, Collectively Evaluated for Impairment	3,828		4,063
Loans Receivable, Individually Evaluated for Impairment	0		0
Unallocated
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for loan losses - Beginning Balance	237	24
Charge-offs	0	0
Recoveries	0	0
Provision for loan losses	18	42
Allowance for loan losses - Ending Balance	255	$ 66
Allowance for Loan Losses, Collectively Evaluated for Impairment	255		237
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0
Loans, gross	0		0
Loans Receivable, Collectively Evaluated for Impairment	0		0
Loans Receivable, Individually Evaluated for Impairment	$ 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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