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		6 Months Ended
	Nov. 30, 2018	Nov. 30, 2017	Nov. 30, 2018	Nov. 30, 2017
Restructuring Cost and Reserve [Line Items]
Beginning Balance			$ 1,116
Expense (income)			1,428
Payments			(1,488)
Adjustments			(53)
Ending Balance	$ 1,003		1,003
Net gain on sale of assets			(1,962)
Restructuring and other income, net	402	$ (9,694)	(534)	$ (7,390)
Early Retirement And Severance
Restructuring Cost and Reserve [Line Items]
Beginning Balance			1,116
Expense (income)			1,155
Payments			(1,257)
Adjustments			(61)
Ending Balance	953		953
Facility Exit And Other Costs
Restructuring Cost and Reserve [Line Items]
Beginning Balance			0
Expense (income)			273
Payments			(231)
Adjustments			8
Ending Balance	$ 50		$ 50