Deposits - Additional Information (Detail) - USD ($)	Sep. 30, 2023	Sep. 30, 2022
Deposits Liabilities Disclosures [Abstract]
Brokered deposits Total	$ 214,200,000	$ 0
Aggregate amount of time certificates of deposit	71,994,000	$ 14,600,000
Aggregate amount of time certificates of deposit with a minimum denomination	$ 250,000

Amount of interest-bearing domestic third-party deposits placed by or through the assistance of a deposit broker, also known as brokered deposit liabilities.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.12)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479853/942-210-S99-1

Name:	us-gaap_InterestBearingDomesticDepositBrokered
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant