Derivative Instruments (Narrative) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Jun. 30, 2025	Sep. 30, 2024
Carrying Amount
Derivative [Line Items]
Cash collateral received from or held by counterparty	$ 5,977	$ 7,844
Investment securities, available for sale	525,212	526,251
Estimated amount in AOCI to be reclassed in the next 12 months as a reduction to expense	17,562
Cash collateral received from or held by counterparty	5,977	7,844
Investment securities, available for sale	$ 525,212	$ 526,251
Interest Rate Swap \| Cash Flow Hedging [Member] \| Designated as Hedging Instrument
Derivative [Line Items]
Swap weighted average terms	2 years 8 months 12 days	3 years 1 month 6 days
Fair Value	$ 0
U.S. government and agency obligations
Derivative [Line Items]
Investment securities, available for sale	54,003	$ 72,776
U.S. government and agency obligations \| Asset Pledged as Collateral \| Margin requirement
Derivative [Line Items]
Investment securities, available for sale	$ 50,111	$ 68,932

Fair value of cash collateral held by counterparty

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- Definition

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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- Definition

Average remaining period until maturity of the derivative contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

The estimated net amount of unrealized gains or losses on interest rate cash flow hedges as of the balance sheet date expected to be reclassified to earnings within the next twelve months.

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- Definition

Fair value as of the balance sheet date of interest rate derivative assets, net of interest rate derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized on the balance sheet.

+ References

No definition available.

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