Income Taxes - Additional Disclosures (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Operating Loss Carryforwards [Line Items]
Increase (decrease) to the valuation allowance	$ (1.2)
Undistributed losses of foreign subsidiaries	72.5
Undistributed earnings of foreign subsidiaries, estimated taxes recognized upon distribution	3.7
Amount of foreign uncertain tax positions to expire within twelve months	0.8
Income tax penalties and interest expense	0.2	$ 0.3	$ 1.2
Reversal of previously accrued interest and penalties	1.0
Accrued interest and penalties	1.0	$ 1.8	$ 1.5
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	90.5
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	51.3
Tax credit carryforward	$ 1.7