Restructuring and Other Expense (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
	Aug. 31, 2018	Aug. 31, 2017
Restructuring Cost and Reserve [Line Items]
Beginning Balance	$ 1,116
Expense (income)	1,026
Payments	(658)
Adjustments	12
Ending Balance	1,496
Net gain on sale of assets	(1,962)
Restructuring and other income, net	(936)	$ 2,304
Early Retirement And Severance
Restructuring Cost and Reserve [Line Items]
Beginning Balance	1,116
Expense (income)	904
Payments	(658)
Adjustments	2
Ending Balance	1,364
Facility Exit And Other Costs
Restructuring Cost and Reserve [Line Items]
Beginning Balance	0
Expense (income)	122
Payments	0
Adjustments	10
Ending Balance	$ 132