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	12 Months Ended
	May 31, 2018	May 31, 2017	May 31, 2016
Restructuring Cost and Reserve [Line Items]
Beginning Balance	$ 789
Expense	3,031
Payments	(2,805)
Adjustments	101
Ending Balance	1,116	$ 789
Net gain on sale of assets	(10,452)
Restructuring and other income, net	(7,421)	6,411	$ 7,177
Early Retirement And Severance
Restructuring Cost and Reserve [Line Items]
Beginning Balance	253
Expense	2,549
Payments	(1,787)
Adjustments	101
Ending Balance	1,116	253
Facility Exit And Other Costs
Restructuring Cost and Reserve [Line Items]
Beginning Balance	536
Expense	482
Payments	(1,018)
Adjustments	0
Ending Balance	$ 0	$ 536