Related Tax Effects Allocated to Each Components of Other Comprehensive Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Aug. 31, 2014	Aug. 31, 2013
Components Of Other Comprehensive Income Loss [Line Items]
Foreign currency translation adjustments, Gross Amount	$ (1,524)	$ (929)
Foreign currency translation adjustments, Tax Effect	115	376
Foreign currency translation adjustments, Net Amount	(1,409)	(553)
Foreign currency hedge, Gross Amount	597	(362)
Foreign currency hedge, Tax Effect	(232)	138
Foreign currency hedge, Net Amount	365	(224)
Other Comprehensive Income (Loss), before Tax, Total	(927)	(1,291)
Total other comprehensive income, Tax Effect	(117)	514
Total other comprehensive income, Net Amount	$ (1,044)	$ (777)