Summary of Tax Effects on Each Component of OCI (Detail) - USD ($) $ in Thousands	3 Months Ended
	Aug. 31, 2016	Aug. 31, 2015
Components Of Other Comprehensive Income Loss [Line Items]
Other comprehensive income (loss), before tax	$ 423	$ 3,053
Other comprehensive income (loss), tax	(463)	(608)
Other comprehensive income (loss)	(40)	2,445
Foreign Currency Translation
Components Of Other Comprehensive Income Loss [Line Items]
Other comprehensive income (loss), before tax	(665)	1,823
Other comprehensive income (loss)	(665)	1,823
Pension Liability Adjustment
Components Of Other Comprehensive Income Loss [Line Items]
Other comprehensive income (loss), before tax		(8)
Other comprehensive income (loss)		(8)
Cash Flow Hedges
Components Of Other Comprehensive Income Loss [Line Items]
Other comprehensive income (loss), before tax	1,088	1,238
Other comprehensive income (loss), tax	(463)	(608)
Other comprehensive income (loss)	$ 625	$ 630