Retirement-Related Benefit Plans' Impact on Income Before Income Taxes (Detail) - Pension Benefits - USD ($) $ in Thousands	12 Months Ended
	May 31, 2020	May 31, 2019	May 31, 2018
U.S. Plans
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 39,425	$ 37,528	$ 37,859
Interest cost	20,415	21,987	17,518
Expected return on plan assets	(34,291)	(33,867)	(32,342)
Prior service cost	9	118	117
Net actuarial losses recognized	18,516	13,087	14,470
Net Pension Cost	44,074	38,853	37,622
Non-U.S. Plans
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	5,400	4,693	4,620
Interest cost	4,842	5,420	5,025
Expected return on plan assets	(7,118)	(7,907)	(8,270)
Prior service cost	(36)	(30)	(31)
Net actuarial losses recognized	2,029	1,229	1,758
Curtailment/settlement losses	86	89	128
Net Pension Cost	$ 5,203	$ 3,494	$ 3,230