Retirement-Related Benefit Plans' Impact on Income Before Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended
	Aug. 31, 2016	Aug. 31, 2015
Pension Benefits, U.S. Plans
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 9,401	$ 8,202
Interest cost	4,331	4,499
Expected return on plan assets	(6,252)	(6,437)
Amortization of Prior service cost (credit)	54	58
Amortization of Net actuarial (gains) losses recognized	5,540	4,190
Net Periodic Benefit Cost	13,074	10,512
Pension Benefits, Non-U.S. Plans
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	1,127	1,067
Interest cost	1,224	1,323
Expected return on plan assets	(1,886)	(1,983)
Amortization of Net actuarial (gains) losses recognized	573	457
Net Periodic Benefit Cost	1,038	864
Postretirement Benefits, U.S. Plans
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	57	59
Amortization of Prior service cost (credit)	(58)	(62)
Net Periodic Benefit Cost	(1)	(3)
Postretirement Benefits, Non-U.S. Plans
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	284	281
Interest cost	222	221
Amortization of Net actuarial (gains) losses recognized	60	61
Net Periodic Benefit Cost	$ 566	$ 563