Retirement-Related Benefit Plans' Impact on Income Before Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Nov. 30, 2019	Nov. 30, 2018	Nov. 30, 2019	Nov. 30, 2018
Pension Benefits | U.S. Plans
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 9,856	$ 9,382	$ 19,712	$ 18,764
Interest cost	5,104	5,497	10,208	10,994
Expected return on plan assets	(8,573)	(8,467)	(17,146)	(16,934)
Prior service cost (credit)	2	29	4	58
Net actuarial (gains) losses recognized	4,629	3,272	9,258	6,544
Net Periodic Benefit (Credit) Cost	11,018	9,713	22,036	19,426
Pension Benefits | Non-U.S. Plans
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	1,391	1,219	2,782	2,438
Interest cost	1,193	1,399	2,386	2,798
Expected return on plan assets	(1,834)	(2,051)	(3,668)	(4,102)
Prior service cost (credit)	(9)	(8)	(18)	(16)
Net actuarial (gains) losses recognized	523	319	1,046	638
Net Periodic Benefit (Credit) Cost	1,264	878	2,528	1,756
Postretirement Benefits | U.S. Plans
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	37	48	74	96
Prior service cost (credit)	(55)	(55)	(110)	(110)
Net actuarial (gains) losses recognized	(16)	(6)	(32)	(12)
Net Periodic Benefit (Credit) Cost	(34)	(13)	(68)	(26)
Postretirement Benefits | Non-U.S. Plans
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	429	392	858	784
Interest cost	282	291	564	582
Net actuarial (gains) losses recognized	158	115	316	230
Net Periodic Benefit (Credit) Cost	$ 869	$ 798	$ 1,738	$ 1,596