Derivative Financial Instruments - Schedule of Derivative Instruments and Hedging Activities Disclosures (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Derivative Instruments Gain Loss [Line Items]
Loss recognized in Other comprehensive income ("OCI")	$ (17,863)	$ (16,315)	$ (7,516)
Foreign Exchange Forward Contract and Options | Not Designated as Hedging Instrument | Other income (expense), net
Derivative Instruments Gain Loss [Line Items]
Net realized and unrealized loss, excluding the underlying foreign currency exposure being hedged	(5,204)	(6,238)	(11,757)
Forward Contracts | Designated as Hedging Instrument | Net Investment Hedging
Derivative Instruments Gain Loss [Line Items]
Loss recognized in Other comprehensive income ("OCI")	(23,684)	(21,643)	(10,033)
Gain (loss) reclassified from OCI to earnings	0	0	0
Gain recognized, excluded portion	$ 6,251	$ 4,346	$ 4,241