Balance Sheet Components - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2025	Mar. 31, 2024	Sep. 30, 2024
Balance Sheet Related Disclosures [Abstract]
Accounts receivable, allowance for credit loss	$ 700,000		$ 700,000		$ 700,000
Other inventory, materials, supplies and merchandise under consignment, gross	0		0		$ 0
Depreciation	$ 6,400,000	$ 7,000,000.0	$ 12,800,000	$ 13,900,000