Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenue
Net Sales	$ 445.9	$ 370.6	$ 1,194.2	$ 992.3
Shakes and other beverages
Disaggregation of Revenue
Net Sales	349.3	295.7	946.2	786.7
Powders
Disaggregation of Revenue
Net Sales	81.9	61.0	211.8	170.9
Other
Disaggregation of Revenue
Net Sales	$ 14.7	$ 13.9	$ 36.2	$ 34.7