Income Taxes - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
Tax Credit Carryforward [Line Items]
Tax benefits from various tax return true ups	$ 5.1
Deferred tax assets restructuring charges	23.8
Valuation allowances	90.7	$ 50.2
Tax benefits of reversal of taxes on unremitted foreign earnings		16.8
Tax benefit		28.7
Tax impact related to tax holidays		$ 0.7
Impact of tax holidays on diluted earnings per share (in dollars per share)		$ 0.01
Operating loss carryforwards	27.9
Net operating loss carryforwards, not subject to expiration	0.4
State Income Tax Credit Carryforwards
Tax Credit Carryforward [Line Items]
Tax credit carryforward	2.9
Foreign Tax Jurisdiction
Tax Credit Carryforward [Line Items]
Tax credit carryforward	$ 4.2