Basis of Presentation - Losses Recognized in Income for Derivative Instruments (Detail) (Foreign exchange forward contracts, Selling, general and administrative expenses, USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Nov. 30, 2014	Nov. 30, 2013	Nov. 30, 2014	Nov. 30, 2013
Foreign exchange forward contracts | Selling, general and administrative expenses
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) recognized in income for derivative instruments	$ 508	$ (147)	$ 381	$ (234)