Commitments and Contingencies - Letters of Credit (Details) - Line of Credit - USD ($) $ in Millions	Sep. 30, 2025	Sep. 30, 2024	Jun. 30, 2022
Debt Instrument [Line Items]
Letters of credit outstanding	$ 6.5	$ 8.3
Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 500.0		$ 500.0