Restructuring and Other Income, Net - Schedule of Progression of Liabilities Associated with Restructuring Activities, Combined with Reconciliation to Restructuring and Other Income, Net (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Nov. 30, 2021	Nov. 30, 2020	Nov. 30, 2021	Nov. 30, 2020
Restructuring Cost and Reserve [Line Items]
Beginning Balance				$ 1,220
Expense (income)				(799)
Payments				(172)
Adjustments				(55)
Ending Balance		$ 194		194
Net gain on sale of assets	[1]			(12,637)
Gain on lease buyout	[2]			(842)
Restructuring and other income, net		(2,004)	$ 7,596	(14,278)	$ 9,444
Early Retirement And Severance
Restructuring Cost and Reserve [Line Items]
Beginning Balance				771
Expense (income)				(350)
Payments				(172)
Adjustments				(55)
Ending Balance		194		194
Facility Exit And Other Costs
Restructuring Cost and Reserve [Line Items]
Beginning Balance				449
Expense (income)				(449)
Payments				0
Adjustments				0
Ending Balance		$ 0		$ 0

[1] The net gain on sale of assets during the six months ended November 30, 2021, resulted primarily from the June 8, 2021, sale of our WSP joint venture’s facility in Canton, Michigan.  In connection with the sale, the Company realized net cash proceeds of $19,850,000 resulting in a pre-tax gain of $12,244,000.

[2] On September 10, 2021, the Company executed an agreement to buyout the remaining term of the operating lease at its fabricated products business in Stow, Ohio, for $1,100,000, resulting in a pre-tax gain of $842,000.  This facility was retained in connection with the divestiture of the Company’s former engineered cabs business and has not been operational since June of calendar 2020.