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