Income Taxes - Deferreds (Details) - Noncurrent - USD ($) $ in Millions	Sep. 30, 2025	Sep. 30, 2024
Deferred tax assets
Income Tax Disclosure
Deferred tax assets, accrued liabilities	$ 26.4	$ 6.7
Deferred tax assets, employee compensation	4.1	5.0
Deferred Tax Assets, Capitalized research and development	8.6	4.7
Deferred tax assets, inventory	4.5	4.2
Deferred tax assets, share-based compensation cost	2.3	3.0
Deferred Tax Liabilities, Leasing Arrangements	6.0	1.0
Deferred tax assets (liabilities), intangible assets	0.0	0.0
Deferred Tax Assets, Leasing Arrangements	0.0	0.0
Deferred tax liabilities, property, plant and equipment	0.0	0.0
Deferred Tax Assets, Other	0.0	0.0
Deferred tax assets, net	51.9	24.6
Deferred tax liability
Income Tax Disclosure
Deferred tax assets, accrued liabilities	0.0	0.0
Deferred tax assets, employee compensation	0.0	0.0
Deferred Tax Assets, Capitalized research and development	0.0	0.0
Deferred tax assets, inventory	0.0	0.0
Deferred tax assets, share-based compensation cost	0.0	0.0
Deferred Tax Liabilities, Leasing Arrangements	0.0	0.0
Deferred tax assets (liabilities), intangible assets	(13.1)	(10.9)
Deferred Tax Assets, Leasing Arrangements	(6.0)	(1.0)
Deferred tax liabilities, property, plant and equipment	(0.4)	(0.2)
Deferred tax liabilities, other	(0.4)	0.0
Deferred tax liabilities, net	(19.9)	(12.1)
Total deferred income taxes
Income Tax Disclosure
Deferred tax assets, accrued liabilities	26.4	6.7
Deferred tax assets, employee compensation	4.1	5.0
Deferred Tax Assets, Capitalized research and development	8.6	4.7
Deferred tax assets, inventory	4.5	4.2
Deferred tax assets, share-based compensation cost	2.3	3.0
Deferred Tax Liabilities, Leasing Arrangements	6.0	1.0
Deferred tax assets (liabilities), intangible assets	(13.1)	(10.9)
Deferred Tax Assets, Leasing Arrangements	(6.0)	(1.0)
Deferred tax liabilities, property, plant and equipment	(0.4)	(0.2)
Deferred Tax Assets, Other	(0.4)	0.0
Deferred tax assets, net	$ 32.0	$ 12.5