Schedule of Progression of Liabilities Associated with Restructuring Activities, Combined with Reconciliation to Restructuring and Other Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Aug. 31, 2016	Aug. 31, 2015
Restructuring Cost and Reserve [Line Items]
Beginning Balance	$ 2,484
Expense	1,217
Payments	(1,419)
Adjustments	8
Ending Balance	2,290
Net (gain) loss on sale of assets	111
Restructuring and other expense	1,328	$ 3,069
Early Retirement And Severance
Restructuring Cost and Reserve [Line Items]
Beginning Balance	1,831
Expense	190
Payments	(890)
Adjustments	8
Ending Balance	1,139
Facility Exit And Other Costs
Restructuring Cost and Reserve [Line Items]
Beginning Balance	653
Expense	1,027
Payments	(529)
Ending Balance	$ 1,151