Changes in Equity - Summary of Changes in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands		3 Months Ended
		Aug. 31, 2018	Aug. 31, 2017
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at May 31, 2018		$ 1,036,375
Income taxes		(460)	$ 1,112
Balance at August 31, 2018		1,037,374
Accumulated Foreign Currency Adjustment Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at May 31, 2018		(4,987)
Other comprehensive loss before reclassifications		(3,678)
Balance at August 31, 2018		(8,665)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at May 31, 2018		(16,071)
Income taxes		(97)
Balance at August 31, 2018		(16,168)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at May 31, 2018		6,478
Other comprehensive loss before reclassifications		(31)
Reclassification adjustments to income	[1]	(2,496)
Income taxes		557
Balance at August 31, 2018		4,508
AOCI Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at May 31, 2018		(14,580)
Other comprehensive loss before reclassifications		(3,709)
Reclassification adjustments to income	[1]	(2,496)
Income taxes		460
Balance at August 31, 2018		$ (20,325)

[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.”