v3.26.1
WBX East Africa and Alpen (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Sep. 30, 2025
Alpen Food Company South Africa (Pty) Limited    
Schedule of Related Party Transactions    
Equity Method Investment, Ownership Percentage 50.00%  
Alpen Food Company South Africa (Pty) Limited | Location, Statement of Financial Position, Balance: us-gaap:EquityMethodInvestments    
Schedule of Related Party Transactions    
Equity method investments $ 5.4 $ 4.5
Post Holdings, Inc. | Weetabix East Africa Limited    
Schedule of Related Party Transactions    
Noncontrolling Interest, Ownership Percentage by Parent 50.20%