Summary of Tax Effects of Each Component of Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	12 Months Ended
	May. 31, 2015	May. 31, 2014	May. 31, 2013
Before-Tax
Foreign currency translation, before tax	$ (34,229)	$ 7,618	$ 5,393
Pension liability adjustment, before tax	(5,652)	(1,555)	3,688
Cash flow hedges, before tax	(18,605)	3,548	1,461
Other comprehensive income (loss), before tax	(58,486)	9,611	10,542
Tax
Foreign currency translation, tax	0	0	0
Pension liability adjustment, tax	1,914	511	(1,415)
Cash flow hedges, tax	6,952	(1,039)	(763)
Other comprehensive income (loss), tax	8,866	(528)	(2,178)
Net-of-tax
Foreign currency translation, net-of-tax	(34,229)	7,618	5,393
Pension liability adjustment, net-of-tax	(3,738)	(1,044)	2,273
Cash flow hedges, net-of-tax	(11,653)	2,509	698
Other comprehensive income (loss), net-of-tax	$ (49,620)	$ 9,083	$ 8,364