Accumulated Other Comprehensive Income - Related Tax Effects Allocated to Each Component of Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Nov. 30, 2015	Nov. 30, 2014	Nov. 30, 2015	Nov. 30, 2014
Components Of Other Comprehensive Income Loss [Line Items]
Foreign currency translation adjustments, Gross Amount	$ (2,043)	$ (5,415)	$ (6,020)	$ (6,939)
Foreign currency translation adjustments, Tax Effect			1,594	1,336
Foreign currency translation adjustments, Net Amount			(4,426)	(5,603)
Foreign currency hedge, Gross Amount	743	842	505	1,439
Foreign currency hedge, Tax Effect			(192)	(559)
Foreign currency hedge, Net Amount			313	880
Other Comprehensive Income (Loss), before Tax, Total			(5,515)	(5,500)
Total other comprehensive income, Tax Effect	$ 30	$ 894	1,402	777
Total other comprehensive income, Net Amount			$ (4,113)	$ (4,723)