Changes in Equity - Summary of Changes in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Feb. 29, 2020	Feb. 28, 2019	Feb. 29, 2020	Feb. 28, 2019
Accumulated Other Comprehensive Income Loss [Line Items]
Balance		$ 958,743	$ 986,255	$ 948,394	$ 1,036,375
Income tax effect		678	(237)	1,108	(2,101)
Balance		972,193	977,008	972,193	977,008
Accumulated Foreign Currency Adjustment Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Balance				(19,640)	(4,987)
Other comprehensive income (loss) before reclassifications				2,372	(8,813)
Reclassification adjustments to income	[1]			8,496	0
Income tax effect				0	0
Balance		(8,772)	(13,800)	(8,772)	(13,800)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Balance				(17,855)	(16,071)
Other comprehensive income (loss) before reclassifications				271	48
Reclassification adjustments to income	[1]			1,326	0
Income tax effect				(351)	(108)
Balance		(16,609)	(16,131)	(16,609)	(16,131)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Balance				(5,969)	6,478
Other comprehensive income (loss) before reclassifications				(6,369)	(4,495)
Reclassification adjustments to income	[1]			9,859	(4,942)
Income tax effect				(757)	2,209
Balance		(3,236)	(750)	(3,236)	(750)
AOCI Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Balance		(30,338)	(31,570)	(43,464)	(14,580)
Other comprehensive income (loss) before reclassifications				(3,726)	(13,260)
Reclassification adjustments to income	[1]			19,681	(4,942)
Income tax effect				(1,108)	2,101
Balance		$ (28,617)	$ (30,681)	$ (28,617)	$ (30,681)

[1]   (a) The statement of earnings classifications of amounts reclassified to income include:    (1) Foreign currency translation – result of $7,454,000 related to the sale of our cryogenics business in Turkey; and $1,042,000 related to the impairment of our Nisshin joint venture.   (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 Q – Derivative Instruments and Hedging Activities”.