Loans Receivable and Allowance for Loan and Lease Losses Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Mar. 31, 2018
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses - Beginning Balance	$ 5,126	$ 5,060
Charge-offs	(110)	(115)
Recoveries	166	68
Provision for loan losses	5	120
Allowance for loan losses - Ending Balance	5,187	5,133
Allowance for Loan Losses, Collectively Evaluated for Impairment	4,426		$ 4,811
Allowance for Loan Losses, Individually Evaluated for Impairment	761		315
Loans, gross	451,896		477,753
Loans Receivable, Collectively Evaluated for Impairment	439,501		464,716
Loans Receivable, Individually Evaluated for Impairment	12,395		13,037
One-to-four family
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses - Beginning Balance	1,210	1,663
Charge-offs	(96)	(81)
Recoveries	0	0
Provision for loan losses	739	(64)
Allowance for loan losses - Ending Balance	1,853	1,518
Allowance for Loan Losses, Collectively Evaluated for Impairment	1,618		1,065
Allowance for Loan Losses, Individually Evaluated for Impairment	235		145
Loans, gross	118,871		123,092
Loans Receivable, Collectively Evaluated for Impairment	113,122		116,588
Loans Receivable, Individually Evaluated for Impairment	5,749		6,504
Multifamily
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses - Beginning Balance	1,819	1,213
Charge-offs	0	0
Recoveries	158	0
Provision for loan losses	(590)	14
Allowance for loan losses - Ending Balance	1,387	1,227
Allowance for Loan Losses, Collectively Evaluated for Impairment	1,387		1,744
Allowance for Loan Losses, Individually Evaluated for Impairment	0		75
Loans, gross	99,292		104,865
Loans Receivable, Collectively Evaluated for Impairment	96,856		103,160
Loans Receivable, Individually Evaluated for Impairment	2,436		1,705
Commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses - Beginning Balance	1,052	1,496
Charge-offs	0	0
Recoveries	0	5
Provision for loan losses	(512)	146
Allowance for loan losses - Ending Balance	540	1,647
Allowance for Loan Losses, Collectively Evaluated for Impairment	540		1,052
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0
Loans, gross	128,797		142,304
Loans Receivable, Collectively Evaluated for Impairment	128,302		140,765
Loans Receivable, Individually Evaluated for Impairment	495		1,539
Construction
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses - Beginning Balance	0	106
Charge-offs	0	0
Recoveries	0	0
Provision for loan losses	0	(106)
Allowance for loan losses - Ending Balance	0	0
Allowance for Loan Losses, Collectively Evaluated for Impairment	0		0
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
Business
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses - Beginning Balance	1,003	573
Charge-offs	(11)	(20)
Recoveries	5	59
Provision for loan losses	172	112
Allowance for loan losses - Ending Balance	1,169	724
Allowance for Loan Losses, Collectively Evaluated for Impairment	643		908
Allowance for Loan Losses, Individually Evaluated for Impairment	526		95
Loans, gross	99,974		102,203
Loans Receivable, Collectively Evaluated for Impairment	96,259		98,914
Loans Receivable, Individually Evaluated for Impairment	3,715		3,289
Consumer
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses - Beginning Balance	18	9
Charge-offs	(3)	(14)
Recoveries	3	4
Provision for loan losses	154	18
Allowance for loan losses - Ending Balance	172	$ 17
Allowance for Loan Losses, Collectively Evaluated for Impairment	172		18
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0
Loans, gross	4,962		5,289
Loans Receivable, Collectively Evaluated for Impairment	4,962		5,289
Loans Receivable, Individually Evaluated for Impairment	0		0
Unallocated
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses - Beginning Balance	24
Charge-offs	0
Recoveries	0
Provision for loan losses	42
Allowance for loan losses - Ending Balance	66
Allowance for Loan Losses, Collectively Evaluated for Impairment	66		24
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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- Definition

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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