Loans and Allowance for Loan Losses - Credit Risk Profile of Association's Loan Portfolio Based on Rating Category and Payment Activity (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 500,682	$ 493,753	$ 498,578
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	494,913	488,010
Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,057	2,415
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,712	3,318
Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	10
Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0
One- to four-family [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	129,185	129,290	129,266
One- to four-family [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	127,480	127,386
One- to four-family [Member] | Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	927
One- to four-family [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	778	1,904
One- to four-family [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0
One- to four-family [Member] | Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0
Multi-family [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	107,107	104,663	106,400
Multi-family [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	106,835	104,504
Multi-family [Member] | Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0
Multi-family [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	272	159
Multi-family [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0
Multi-family [Member] | Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0
Home equity lines of credit [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	9,131	8,938	9,058
Home equity lines of credit [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	8,980	8,918
Home equity lines of credit [Member] | Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	135
Home equity lines of credit [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	16	20
Home equity lines of credit [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0
Home equity lines of credit [Member] | Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0
Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	20,897	16,113	14,521
Construction [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	20,897	16,113
Construction [Member] | Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0
Construction [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0
Construction [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0
Construction [Member] | Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	143,396	143,367	152,019
Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	141,965	142,076
Commercial [Member] | Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,083	1,040
Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	348	251
Commercial [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0
Commercial [Member] | Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	83,812	84,246	80,350
Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	81,609	81,906
Commercial [Member] | Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,912	1,375
Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	291	965
Commercial [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0
Commercial [Member] | Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	7,154	7,136	$ 6,964
Consumer [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	7,147	7,107
Consumer [Member] | Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0
Consumer [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	7	19
Consumer [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	$ 10
Consumer [Member] | Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 0