Summary of Changes in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Nov. 30, 2017	Nov. 30, 2016	Nov. 30, 2017	Nov. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of May 31, 2017				$ 1,073,929
Income taxes		$ 1,285	$ (395)	173	$ (858)
Balance as of November 30, 2017		1,042,783		1,042,783
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of May 31, 2017				(17,358)
Other comprehensive income before reclassifications				17,024
Balance as of November 30, 2017		(334)		(334)
Pension Liability Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of May 31, 2017				(14,819)
Income taxes				(6)
Balance as of November 30, 2017		(14,825)		(14,825)
Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of May 31, 2017				4,402
Other comprehensive income before reclassifications				8,912
Reclassification adjustments to income	[1]			(9,414)
Income taxes				179
Balance as of November 30, 2017		4,079		4,079
Accumulated Other Comprehensive Loss, Net of Tax
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of May 31, 2017				(27,775)
Other comprehensive income before reclassifications				25,936
Reclassification adjustments to income	[1]			(9,414)
Income taxes				173
Balance as of November 30, 2017		$ (11,080)		$ (11,080)

[1] The statement of earnings classification of amounts reclassified to income for cash flow hedges is disclosed in "NOTE O - Derivative Instruments and Hedging Activities."