Financial Instruments and Risk Management (Narrative) (Details) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2024 USD ($) contracts	Dec. 31, 2023 USD ($)	Sep. 30, 2024 USD ($)
Derivative [Line Items]
Long-term debt	$ 1,449.0		$ 1,284.0
Fixed rate
Derivative [Line Items]
Long-term debt	1,250.0		1,250.0
Fair value of long-term debt	$ 1,162.4		1,180.0
Not designated as hedge | FX contract
Derivative [Line Items]
Open foreign currency contracts | contracts	1
Derivative, notional amount	$ 9.0
Gain (loss) recognized in income	$ 0.9	$ 1.1
Cash flow hedge | Designated as hedge | FX contract
Derivative [Line Items]
Open foreign currency contracts | contracts	64
Derivative, notional amount	$ 99.7
Gain (loss) recognized in OCI	$ 4.8		$ (2.4)