Fair Value Measurements and Derivative Instruments - Summary of Effects on Consolidated Financial Statements of Designated As Cash Flow Hedges (Details) - Cash Flow Hedges - Designated - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Interest Rate Swaps
Derivative Instruments Gain Loss [Line Items]
Derivative Instrument, Gain (Loss) Reclassified from AOCI into Income, Effective Portion, Statement of Income or Comprehensive Income [Extensible Enumeration]	Interest Expense	Interest Expense
Income recognized in Other comprehensive income (loss)	$ 1.5	$ 2.6	$ 1.5	$ 3.7
Net income (loss) reclassified from Accumulated other comprehensive (loss) income into Interest expense	$ 1.3	$ (0.7)	4.3	(1.6)
Fuel Swap Contracts
Derivative Instruments Gain Loss [Line Items]
Derivative Instrument, Gain (Loss) Reclassified from AOCI into Income, Effective Portion, Statement of Income or Comprehensive Income [Extensible Enumeration]	Cost of Goods and Services Sold	Cost of Goods and Services Sold
Income recognized in Other comprehensive income (loss)	$ 0.0	$ 0.0	0.0	0.2
Net income (loss) reclassified from Accumulated other comprehensive (loss) income into Interest expense	$ 0.0	$ 0.0	$ 0.0	$ 1.5