Related Tax Effects Allocated to Each Components of Other Comprehensive Income (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	May 31, 2013	May 31, 2012	May 31, 2011
Components Of Other Comprehensive Income Loss [Line Items]
Foreign currency translation adjustments, Gross Amount	$ 1,070	$ (8,264)	$ 8,349
Foreign currency translation adjustments, Tax Effect	130	1,246	(1,368)
Foreign currency translation adjustments, Net Amount	1,200	(7,018)	6,981
Foreign currency hedge, Gross Amount	(674)	2,385	(2,587)
Foreign currency hedge, Tax Effect	281	(928)	1,001
Foreign currency hedge, Net Amount	(393)	1,457	(1,586)
Other Comprehensive Income (Loss), before Tax, Total	396	(5,879)	5,762
Total other comprehensive income, Tax Affect	411	318	(367)
Total other comprehensive income, Net Amount	$ 807	$ (5,561)	$ 5,395