Fair Value - Assets Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Financial Assets
Available for sale, at fair value	$ 10,889	$ 12,285
Loan servicing rights	4,479	4,353
Derivatives	445
U.S. GSE residential mortgage-backed securities
Financial Assets
Available for sale, at fair value	142	242
Corporate Bonds
Financial Assets
Available for sale, at fair value	10,747	12,043
Recurring \| Carrying Amount
Financial Assets
Loan servicing rights	4,479
Derivatives	445
Total	15,813	16,638
Recurring \| Carrying Amount \| U.S. GSE residential mortgage-backed securities
Financial Assets
Available for sale, at fair value	142	242
Recurring \| Carrying Amount \| Corporate Bonds
Financial Assets
Available for sale, at fair value	10,747	12,043
Recurring \| Carrying Amount \| Loan servicing rights
Financial Assets
Loan servicing rights		4,353
Recurring \| Estimate of Fair Value Measurement [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial Assets
Loan servicing rights	0
Derivatives	0
Total	0	0
Recurring \| Estimate of Fair Value Measurement [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| U.S. GSE residential mortgage-backed securities
Financial Assets
Available for sale, at fair value	0	0
Recurring \| Estimate of Fair Value Measurement [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Corporate Bonds
Financial Assets
Available for sale, at fair value	0	0
Recurring \| Estimate of Fair Value Measurement [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Loan servicing rights
Financial Assets
Loan servicing rights		0
Recurring \| Estimate of Fair Value Measurement [Member] \| Significant Other Observable Inputs (Level 2)
Financial Assets
Loan servicing rights	0
Derivatives	445
Total	11,334	12,285
Recurring \| Estimate of Fair Value Measurement [Member] \| Significant Other Observable Inputs (Level 2) \| U.S. GSE residential mortgage-backed securities
Financial Assets
Available for sale, at fair value	142	242
Recurring \| Estimate of Fair Value Measurement [Member] \| Significant Other Observable Inputs (Level 2) \| Corporate Bonds
Financial Assets
Available for sale, at fair value	10,747	12,043
Recurring \| Estimate of Fair Value Measurement [Member] \| Significant Other Observable Inputs (Level 2) \| Loan servicing rights
Financial Assets
Loan servicing rights		0
Recurring \| Estimate of Fair Value Measurement [Member] \| Significant Unobservable Inputs (Level 3)
Financial Assets
Loan servicing rights	4,479
Derivatives	0
Total	4,479	4,353
Recurring \| Estimate of Fair Value Measurement [Member] \| Significant Unobservable Inputs (Level 3) \| U.S. GSE residential mortgage-backed securities
Financial Assets
Available for sale, at fair value	0	0
Recurring \| Estimate of Fair Value Measurement [Member] \| Significant Unobservable Inputs (Level 3) \| Corporate Bonds
Financial Assets
Available for sale, at fair value	$ 0	0
Recurring \| Estimate of Fair Value Measurement [Member] \| Significant Unobservable Inputs (Level 3) \| Loan servicing rights
Financial Assets
Loan servicing rights		$ 4,353

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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