Retirement-Related Benefit Plans' Impact on Income Before Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended
	Aug. 31, 2015	Aug. 31, 2014
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 9,600
Interest cost	6,100
Pension Benefits, U.S. Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	8,202	$ 7,564
Interest cost	4,499	5,002
Expected return on plan assets	(6,437)	(6,034)
Prior service cost (credit)	58	74
Net actuarial (gains) losses recognized	4,190	3,472
Net Periodic Benefit Cost	10,512	10,078
Pension Benefits, Non-U.S. Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	1,067	1,231
Interest cost	1,323	1,891
Expected return on plan assets	(1,983)	(2,296)
Prior service cost (credit)		10
Net actuarial (gains) losses recognized	457	487
Net Periodic Benefit Cost	864	1,323
Postretirement Benefits, U.S. Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	59	66
Prior service cost (credit)	(62)	(62)
Net actuarial (gains) losses recognized		(34)
Net Periodic Benefit Cost	(3)	(30)
Postretirement Benefits, Non-U.S. Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	281	313
Interest cost	221	308
Net actuarial (gains) losses recognized	61	104
Net Periodic Benefit Cost	$ 563	$ 725