Summary of Significant Accounting Policies - Property (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Property, Plant and Equipment [Line Items]
Depreciation	$ 1.6	$ 1.5	$ 1.7
Property, Plant and Equipment, Net
Property, at cost	33.2	21.4
Accumulated depreciation	(14.2)	(12.2)
Property, net	19.0	9.2
Land and land improvements
Property, Plant and Equipment, Net
Property, at cost	0.8	0.8
Building and building improvements
Property, Plant and Equipment, Net
Property, at cost	$ 5.5	4.5
Building and building improvements | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	1 year
Building and building improvements | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	33 years
Machinery and equipment
Property, Plant and Equipment, Net
Property, at cost	$ 15.5	14.3
Machinery and equipment | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	3 years
Machinery and equipment | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	10 years
Construction in progress
Property, Plant and Equipment, Net
Property, at cost	$ 10.0	0.6
Software and Software Development Costs
Property, Plant and Equipment, Net
Property, at cost	$ 1.4	1.2
Software and Software Development Costs | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	1 year
Software and Software Development Costs | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	5 years
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 13.5	$ 8.1