Income Taxes - Additional Disclosures (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Operating Loss Carryforwards [Line Items]
Accrued GILTI taxes payable	$ 0.7
Decrease to the valuation allowance	1.2
Undistributed losses of foreign subsidiaries	98.2
Undistributed earnings of foreign subsidiaries, estimated taxes recognized upon distribution	5.0
Amount of foreign uncertain tax positions to expire within twelve months	0.7
Income tax penalties and interest expense (benefit)	0.5	$ 0.2	$ (0.8)
Reversal of previously accrued interest and penalties	0.4
Accrued interest and penalties	0.8	$ 0.7	$ 1.0
Undistributed foreign earnings	20.0
Liability	1.0
Domestic Tax Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	5.2
Foreign Tax Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	47.1
Tax credit carryforward	$ 1.7