Summary of Tax Years Open to Examination by Major Tax Jurisdiction (Parenthetical) (Detail)	12 Months Ended
	May 31, 2012
UNITED STATES | Federal
Income Tax Examination [Line Items]
Open tax years	2008
UNITED STATES | State and Local Jurisdiction
Income Tax Examination [Line Items]
Open tax years	2005
AUSTRIA
Income Tax Examination [Line Items]
Open tax years	2006
CANADA
Income Tax Examination [Line Items]
Open tax years	2008