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Restructuring (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
Restructuring (Details) - USD ($) $ in Millions	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Restructuring Reserve
Restructuring Charges (Adjustments)	$ 8.5	$ 0.8	$ 9.7	$ 8.9
Sparks Facility
Restructuring Reserve
Balance, Beginning of Period			3.2
Restructuring Charges (Adjustments)			1.6
Cash payments			(4.8)
Non-cash charges			0.0
Balance, End of Period	0.0		0.0
Total expected restructuring charges	7.2		7.2
Cumulative restructuring charges incurred to date	6.3		6.3
Remaining expected restructuring charges	0.9		0.9
Cobourg Facility
Restructuring Reserve
Balance, Beginning of Period			4.2
Restructuring Charges (Adjustments)			0.1
Cash payments			(4.2)
Non-cash charges			0.0
Balance, End of Period	0.1		0.1
Total expected restructuring charges	4.3		4.3
Cumulative restructuring charges incurred to date	4.3		4.3
Remaining expected restructuring charges	0.0		0.0
Sparks Facility and Cobourg Facility
Restructuring Reserve
Balance, Beginning of Period			7.4
Restructuring Charges (Adjustments)			1.7
Cash payments			(9.0)
Non-cash charges			0.0
Balance, End of Period	0.1		0.1
Total expected restructuring charges	11.5		11.5
Cumulative restructuring charges incurred to date	10.6		10.6
Remaining expected restructuring charges	$ 0.9		$ 0.9