Summary of Significant Accounting Policies - Property (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Property, Plant and Equipment [Line Items]
Depreciation	$ 1.5	$ 1.7	$ 1.6
Property, Plant and Equipment, Net
Property, at cost	21.4	24.0
Accumulated depreciation	(12.2)	(15.5)
Property, net	9.2	8.5
Land and land improvements
Property, Plant and Equipment, Net
Property, at cost	0.8	0.7
Building and building improvements
Property, Plant and Equipment, Net
Property, at cost	$ 4.5	5.6
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	$ 14.3	14.1
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
Computer software, intangible asset
Property, Plant and Equipment, Net
Property, at cost	$ 1.2	2.4
Computer software, intangible asset | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	1 year
Computer software, intangible asset | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	5 years
Construction in progress
Property, Plant and Equipment, Net
Property, at cost	$ 0.6	1.2
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 8.1	$ 7.1