Income Taxes - Summary of Tax Years Open to Examination by Major Tax Jurisdiction (Detail)	12 Months Ended
	May 31, 2018
State and Local Jurisdiction
Income Tax Examination [Line Items]
Open tax years	2013
U.S. | United States
Income Tax Examination [Line Items]
Open tax years	2015
Federal Ministry of Finance, Austria | Non - United States
Income Tax Examination [Line Items]
Open tax years	2013
Canada Revenue Agency | Non - United States
Income Tax Examination [Line Items]
Open tax years	2014
Mexican Tax Authority | Non - United States
Income Tax Examination [Line Items]
Open tax years	2013
Portugal | Non - United States
Income Tax Examination [Line Items]
Open tax years	2014