Changes in Equity - Summary of Changes in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Nov. 30, 2020	Nov. 30, 2019	Nov. 30, 2020	Nov. 30, 2019
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	$ 1,529,900	$ 907,442	$ 966,433	$ 948,394
Income tax effect	(4,346)	(825)	(4,452)	(430)
Balance	1,430,471	958,743	1,430,471	958,743
Foreign Currency Translation
Accumulated Other Comprehensive Income Loss [Line Items]
Balance			(9,142)	(19,639)
Other comprehensive income (loss) before reclassifications			6,581	2,948
Reclassification adjustments to income			0	8,496	[1]
Income tax effect			676	0
Balance	(1,885)	(8,195)	(1,885)	(8,195)
Pension Liability Adjustment
Accumulated Other Comprehensive Income Loss [Line Items]
Balance			(21,886)	(17,856)
Other comprehensive income (loss) before reclassifications			484	79
Reclassification adjustments to income			0	1,342	[1]
Income tax effect			(116)	(313)
Balance	(21,518)	(16,748)	(21,518)	(16,748)
Cash Flow Hedges
Accumulated Other Comprehensive Income Loss [Line Items]
Balance			(4,189)	(5,969)
Other comprehensive income (loss) before reclassifications			16,765	(5,975)
Reclassification adjustments to income			6,028	6,666	[1]
Income tax effect			(5,013)	(117)
Balance	13,591	(5,395)	13,591	(5,395)
Accumulated Other Comprehensive Loss, Net of Tax
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(23,975)	(40,308)	(35,217)	(43,464)
Other comprehensive income (loss) before reclassifications			23,830	(2,948)
Reclassification adjustments to income			6,028	16,504	[1]
Income tax effect			(4,453)	(430)
Balance	$ (9,812)	$ (30,338)	$ (9,812)	$ (30,338)

[1]   (a)  The statement of earnings (loss) classification of amounts reclassified to income include: (1)  Foreign currency translation – result of $7,454,000 related to the sale of the cryogenics business in Turkey; and $1,042,000 related to the impairment of Nisshin, the Company’s former joint venture in China. (2)  Pension liability adjustment – result of the settlement of certain participant balances within the pension plan maintained by WAVE. (3)  Cash flow hedges – disclosed in “NOTE P – Derivative Instruments and Hedging Activities”.