Summary of Tax Effects of Each Component of Other Comprehensive Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Aug. 31, 2012	Aug. 31, 2011
Before-Tax amount
Foreign currency translation, before tax amount	$ 3,908
Pension liability adjustment, before tax amount	(255)
Cash flow hedges, before tax amount	1,224
Other comprehensive income, before tax amount	4,877
Tax Expense
Foreign currency translation, tax expense
Pension liability adjustment, tax expense	83
Cash flow hedges, tax expense	(240)
Other comprehensive income, tax expense	(157)
Net-of-Tax amount
Foreign currency translation	3,908	(300)
Pension liability adjustment	(172)
Cash flow hedges	984	(2,035)
Other comprehensive income	$ 4,720	$ (2,335)