v3.26.1
Revenue Recognition - Revenue by Product Class and Timing (Detail) - USD ($)
$ in Millions
12 Months Ended
May 31, 2026
May 31, 2025
May 31, 2024
Disaggregation Of Revenue [Line Items]      
Net sales $ 3,443.8 $ 3,093.3 $ 3,430.6
Direct | Steel Processing      
Disaggregation Of Revenue [Line Items]      
Net sales 3,323.7 2,943.4 3,269.4
Toll | Steel Processing      
Disaggregation Of Revenue [Line Items]      
Net sales $ 120.1 $ 149.9 $ 161.2