Fair Value Measurement - Narrative (Details) - USD ($)	6 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Sep. 30, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, measurement with unobservable inputs reconciliation, recurring basis, liability value	$ 1,500,000
Equity Method Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, measurement with unobservable inputs reconciliation, recurring basis, asset, impairment	0	$ 0
Prepaid Expenses and Other Current Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest receivable	$ 1,200,000		$ 1,000,000