Goodwill and Other Long-Lived Assets - Summary of Changes in Carrying Amount of Goodwill (Detail) - USD ($)		12 Months Ended
		May 31, 2023	May 31, 2022
Goodwill [Line Items]
Goodwill, Beginning Balance		$ 401,469,000	$ 351,056,000
Acquisitions and purchase accounting adjustments	[1]	15,146,000	60,547,000
Translation adjustments		(1,795,000)	(10,134,000)
Goodwill, Ending Balance		414,820,000	401,469,000
Steel Processing
Goodwill [Line Items]
Goodwill, Beginning Balance		80,033,000	20,218,000
Acquisitions and purchase accounting adjustments	[1]	(801,000)	60,115,000
Translation adjustments		(590,000)	(300,000)
Goodwill, Ending Balance		78,642,000	80,033,000
Consumer products
Goodwill [Line Items]
Goodwill, Beginning Balance	[2]	241,373,000	240,941,000
Acquisitions and purchase accounting adjustments	[1],[2]	15,947,000	432,000
Goodwill, Ending Balance	[2]	257,320,000	241,373,000
Building Products
Goodwill [Line Items]
Goodwill, Beginning Balance	[2]	65,408,000	72,273,000
Translation adjustments	[2]	(195,000)	(6,865,000)
Goodwill, Ending Balance	[2]	65,213,000	65,408,000
Sustainable Energy Solutions
Goodwill [Line Items]
Goodwill, Beginning Balance	[2]	14,655,000	17,624,000
Translation adjustments	[2]	(1,010,000)	(2,969,000)
Goodwill, Ending Balance	[2]	13,645,000	14,655,000
Other
Goodwill [Line Items]
Goodwill, Beginning Balance		0
Goodwill, Ending Balance		$ 0	$ 0

[1] For additional information regarding our acquisitions, refer to “Note Q - Acquisitions.”

[2] In connection with the realignment of the our legacy Pressure Cylinders business, as discussed further in “Note P - Segment Data”, the goodwill of our legacy Pressure Cylinders business unit was allocated to the new reporting units on a relative fair value basis.