Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Disaggregation of Revenue
Net Sales	$ 385.6	$ 315.2	$ 748.3	$ 621.7
Shakes and other beverages
Disaggregation of Revenue
Net Sales	299.9	246.0	596.9	491.0
Powders
Disaggregation of Revenue
Net Sales	73.8	59.1	129.9	109.9
Other
Disaggregation of Revenue
Net Sales	$ 11.9	$ 10.1	$ 21.5	$ 20.8