Accumulated Other Comprehensive Income (Loss) - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Equity [Abstract]
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	$ 11.6
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax	(2.8)
Foreign currency translation	9.1	$ (11.9)	$ (25.5)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	$ 0.0