Retirement-Related Benefit Plans' Impact on Income Before Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended
	Aug. 31, 2017	Aug. 31, 2016
Pension Benefits | U.S. Plans
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 9,465	$ 9,401
Interest cost	4,379	4,331
Expected return on plan assets	(8,086)	(6,252)
Amortization of Prior service cost (credit)	29	54
Amortization of Net actuarial losses recognized	3,618	5,540
Net Periodic Benefit Cost	9,405	13,074
Pension Benefits | Non-U.S. Plans
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	1,175	1,127
Interest cost	1,145	1,224
Expected return on plan assets	(1,978)	(1,886)
Amortization of Prior service cost (credit)	(6)
Amortization of Net actuarial losses recognized	419	573
Net Periodic Benefit Cost	755	1,038
Postretirement Benefits | U.S. Plans
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	43	57
Amortization of Prior service cost (credit)	(55)	(58)
Amortization of Net actuarial losses recognized	6
Net Periodic Benefit Cost	(6)	(1)
Postretirement Benefits | Non-U.S. Plans
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	311	284
Interest cost	224	222
Amortization of Net actuarial losses recognized	79	60
Net Periodic Benefit Cost	$ 614	$ 566