Derivatives - Summary of Location and Fair Values of Derivative Instruments (Details) - Designated as Hedging Instrument [Member] - Cash Flow Hedging [Member] - Natural Gas Commodity Hedge [Member] - USD ($) $ in Millions		Dec. 31, 2023	Sep. 30, 2023
Derivative [Line Items]
Derivative Liability	[1]	$ 16.6	$ 6.3
Derivative Liability, Statement of Financial Position [Extensible Enumeration]		Other Liabilities, Current	Other Liabilities, Current

[1] At December 31, 2023 and September 30, 2023, liability positions by counterparty were partially offset by $0.2 million and $0.2 million, respectively, of asset positions where we had an enforceable right of netting.