Accumulated Other Comprehensive Income (loss) (Detail) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2021	May 31, 2020	May 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ 1,264,663	$ 1,408,605	$ 1,633,538
Deferred taxes	27,783	(23,403)	(19,068)
Ending Balance	1,743,025	1,264,663	1,408,605
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(440,732)	(370,495)	(300,013)
Other comprehensive income (loss)	148,360	(71,820)	(73,660)
Deferred taxes	(7,993)	1,583	3,178
Ending Balance	(300,365)	(440,732)	(370,495)
Pension And Other Postretirement Benefit Liability Adjustments, Net of Tax
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(277,717)	(211,645)	(157,495)
Other comprehensive income (loss)	113,984	(86,347)	(70,785)
Deferred taxes	(26,877)	20,275	16,635
Ending Balance	(190,610)	(277,717)	(211,645)
Unrealized Gain (Loss) On Derivatives, Net of Tax
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(71)	4,379	(131)
Other comprehensive income (loss)	(31,087)	(6,315)	4,713
Deferred taxes	7,176	1,865	(203)
Ending Balance	(23,982)	(71)	4,379
Unrealized Gain (Loss) On Securities, Net of Tax
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	1,023	133	(1,409)
Reclassification adjustments for gains (losses) included in net income, net of taxes of $151, $591, $401 in 2020, 2019 and 2018	191		1,777
Other comprehensive income (loss)	(1,052)	1,210	307
Deferred taxes	(89)	(320)	(542)
Ending Balance	73	1,023	133
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(717,497)	(577,628)	(459,048)
Reclassification adjustments for gains (losses) included in net income, net of taxes of $151, $591, $401 in 2020, 2019 and 2018	191		1,777
Other comprehensive income (loss)	230,205	(163,272)	(139,425)
Deferred taxes	(27,783)	23,403	19,068
Ending Balance	$ (514,884)	$ (717,497)	$ (577,628)