Summary of Tax Effects on Each Component of Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015
Components Of Other Comprehensive Income Loss [Line Items]
Other comprehensive income (loss), before tax	$ 220	$ 37,007	$ (58,486)
Other comprehensive income (loss), tax	542	(12,141)	8,866
Other comprehensive income (loss)	762	24,866	(49,620)
Foreign Currency Translation
Components Of Other Comprehensive Income Loss [Line Items]
Other comprehensive income (loss), before tax	1,342	4,716	(34,229)
Other comprehensive income (loss)	1,342	4,716	(34,229)
Pension Liability Adjustment
Components Of Other Comprehensive Income Loss [Line Items]
Other comprehensive income (loss), before tax	3,400	(3,233)	(5,652)
Other comprehensive income (loss), tax	(1,158)	1,175	1,914
Other comprehensive income (loss)	2,242	(2,058)	(3,738)
Cash Flow Hedges
Components Of Other Comprehensive Income Loss [Line Items]
Other comprehensive income (loss), before tax	(4,522)	35,524	(18,605)
Other comprehensive income (loss), tax	1,700	(13,316)	6,952
Other comprehensive income (loss)	$ (2,822)	$ 22,208	$ (11,653)