Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disaggregation of Revenue
Net Sales	$ 515.4	$ 445.9	$ 1,440.4	$ 1,194.2
Shakes and other beverages
Disaggregation of Revenue
Net Sales	411.9	349.3	1,160.0	946.2
Powders
Disaggregation of Revenue
Net Sales	90.1	81.9	243.9	211.8
Other
Disaggregation of Revenue
Net Sales	$ 13.4	$ 14.7	$ 36.5	$ 36.2