Inventory (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Inventory [Line Items]
Impairment charges	$ 0.0	$ 0.0	$ 14.0	$ 3.8
Write-offs (recoveries) of earnest money deposits and pre-acquisition costs	$ 10.8	$ 10.6	$ 48.2	$ 26.8