Commitment and Contingencies - Schedule of Allowance for Credit Losses for Unfunded Loan Commitments (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Off-Balance-Sheet, Credit Loss, Liability [Roll Forward]
Beginning ACL	$ 320	$ 276	$ 327	$ 332
Provision for (recapture of) credit losses	93	(9)	86	(130)
Ending ACL	$ 413	$ 267	413	267
Cumulative Effect, Period of Adoption, Adjustment
Off-Balance-Sheet, Credit Loss, Liability [Roll Forward]
Beginning ACL			$ 0	$ 65

Amount of expected credit loss for credit exposure on off-balance-sheet commitment, including but not limited to, loan commitment, standby letter of credit, financial guarantee not accounted for as insurance. Excludes off-balance sheet credit exposure accounted for as insurance and instrument accounted for under derivatives and hedging.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482454/460-10-45-1

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