Changes in Benefit Obligation (Detail) - Postretirement Benefits - USD ($) $ in Thousands	12 Months Ended
	May 31, 2021	May 31, 2020	May 31, 2019
Domestic
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation at beginning of year	$ 4,182	$ 4,990
Interest cost	74	149	$ 192
Benefit payments	(1,902)	(1,659)
Actuarial (gains) losses	152	702
Benefit Obligation at End of Year	2,506	4,182	4,990
Non-U.S. Plans
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation at beginning of year	38,389	37,663
Service cost	1,959	1,661	1,507
Interest cost	1,286	1,089	1,122
Benefit payments	(673)	(639)
Actuarial (gains) losses	(6,415)	(683)
Currency exchange rate changes	5,428	(702)
Benefit Obligation at End of Year	$ 39,974	$ 38,389	$ 37,663