Revenue Recognition - Revenue by Product Class and Timing (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Nov. 30, 2023	Nov. 30, 2022	Nov. 30, 2023	Nov. 30, 2022
Disaggregation Of Revenue [Line Items]
Net sales	$ 808.0	$ 868.4	$ 1,713.8	$ 1,943.0
Direct
Disaggregation Of Revenue [Line Items]
Net sales	769.8	833.1	1,639.3	1,870.5
Toll
Disaggregation Of Revenue [Line Items]
Net sales	38.2	35.3	74.5	72.5
Toll | Over time revenue
Disaggregation Of Revenue [Line Items]
Net sales	$ 38.2	$ 35.3	$ 74.5	$ 72.5