Fair Value Measurements - Recurring Basis - Investment in ECOTEC - Unobservable inputs (Details) - ECOTEC $ in Millions	Sep. 30, 2024 USD ($)	Sep. 30, 2023
Fair value measurement of assets and liabilities
Ownership interest (as a percent)	25.00%
Level 3
Fair value measurement of assets and liabilities
Investment	$ 16.2
Equity investment | Discounted cash flow | WACC | Minimum
Significant unobservable inputs
Equity Securities, FV-NI, Measurement Input	0.004	0.000
Equity investment | Discounted cash flow | WACC | Maximum
Significant unobservable inputs
Equity Securities, FV-NI, Measurement Input	0.200	0.174
Equity investment | Discounted cash flow | WACC | Median
Significant unobservable inputs
Equity Securities, FV-NI, Measurement Input	0.135	0.100
Equity investment | Guideline public company | Revenue multiple | Minimum
Significant unobservable inputs
Equity Securities, FV-NI, Measurement Input	1.5	1.6
Equity investment | Guideline public company | Revenue multiple | Maximum
Significant unobservable inputs
Equity Securities, FV-NI, Measurement Input	7.2	10.0
Equity investment | Guideline public company | Revenue multiple | Median
Significant unobservable inputs
Equity Securities, FV-NI, Measurement Input	3.8	4.0