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Derivatives and Hedging Activities - Impact of Derivative Instruments on AOCI (Details) - Cash flow hedging - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Derivative [Line Items]
Total pre-tax gain/(loss) recognized in AOCI	$ 21,599	$ (40,527)
Pay fixed/receive floating swaps on borrowings cash flow hedges
Derivative [Line Items]
Pay fixed/receive floating swaps on borrowings cash flow hedges	21,594	(40,527)
Reclassification adjustment of net (gain)/loss included in net income	$ 5	$ 0

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+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
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Amount, before tax and after reclassification, of gain (loss) from derivative instrument designated and qualifying cash flow hedge included in assessment of hedge effectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Amount, before tax and reclassification, of gain (loss) from derivative instrument designated and qualifying cash flow hedge included in assessment of hedge effectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Amount, before tax, of reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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