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Loans and Allowance for Credit Losses - Categories of Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022
Real estate loans
Total loans	$ 661,147		$ 594,324	$ 568,240
Unearned fees and discounts, net	(337)		(272)
Allowance for credit losses	7,935	$ 7,450	7,139	7,166	$ 7,023	$ 7,052
Loans, net	653,549		587,457
One- to four-family [Member]
Real estate loans
Total loans	175,817		163,854	150,711
Allowance for credit losses	1,809	1,906	1,898	1,722	1,537	1,028
Multi-family [Member]
Real estate loans
Total loans	128,625		89,649	100,147
Allowance for credit losses	1,865	1,115	1,121	1,402	1,284	1,375
Home equity lines of credit [Member]
Real estate loans
Total loans	9,494		8,066	6,926
Allowance for credit losses	147	134	121	101	94	70
Construction [Member]
Real estate loans
Total loans	39,906		50,973	36,595
Allowance for credit losses	539	1,165	765	585	549	489
Commercial [Member]
Real estate loans
Total loans	215,565		193,707	192,015
Allowance for credit losses	2,593	2,265	2,369	2,392	2,386	1,985
Commercial [Member]
Real estate loans
Total loans	83,698		79,693	72,360
Allowance for credit losses	915	788	794	871	1,090	2,025
Consumer [Member]
Real estate loans
Total loans	8,042		8,382	9,486
Allowance for credit losses	$ 67	$ 77	$ 71	$ 93	$ 83	$ 80