Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation of Revenue
Net Sales	$ 370.6	$ 342.6	$ 992.3	$ 907.1
Shakes and other beverages
Disaggregation of Revenue
Net Sales	295.7	278.6	786.7	740.2
Powders
Disaggregation of Revenue
Net Sales	61.0	49.7	170.9	126.5
Nutrition bars
Disaggregation of Revenue
Net Sales	10.5	11.9	27.4	34.6
Other
Disaggregation of Revenue
Net Sales	$ 3.4	$ 2.4	$ 7.3	$ 5.8