Leases - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Mar. 31, 2022 USD ($) AdministrativeOffice BranchOffice	Mar. 31, 2021 USD ($)	Mar. 31, 2022 USD ($) AdministrativeOffice BranchOffice	Mar. 31, 2021 USD ($)
Lessee Lease Description [Line Items]
Number of branch offices in real estate lease | BranchOffice	11		11
Number of administrative office in real estate lease | AdministrativeOffice	1		1
Lease maturity start year			2022
Lease maturity end year			2041
Lease option to extend			some of which include lessee options to extend the lease term.
Operating lease, weighted average remaining lease terms	9 years 7 months 6 days		9 years 7 months 6 days
Lessee, operating lease, description			The operating lease asset and lease liability are determined at the commencement date of the lease based on the present value of the lease payments.
Operating lease, weighted average discount rate, percent	2.42%		2.42%
Short-term lease cost	$ 0	$ 0	$ 0	$ 0
Sale and leaseback transactions with related parties	0	0	0	0
Operating lease, cost	504,000	$ 501,000	1,500,000	$ 1,500,000
Operating lease, right-of-use asset	$ 8,300,000		$ 8,300,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Other assets		Other assets
Operating lease, liability	$ 8,573,000		$ 8,573,000
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Other liabilities		Other liabilities
Maximum [Member]
Lessee Lease Description [Line Items]
Lessee, operating lease, original term	12 months		12 months