Retirement-Related Benefit Plans' Impact on Income Before Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Aug. 31, 2012	Aug. 31, 2011
Pension Benefits, U.S. Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 6,488	$ 4,977
Interest cost	4,060	3,827
Expected return on plan assets	(4,358)	(4,354)
Amortization of:
Prior service cost	87	88
Net actuarial (gains) losses recognized	4,222	2,127
Net Periodic Benefit Cost	10,499	6,665
Pension Benefits, Non-U.S. Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	1,050	965
Interest cost	1,769	2,040
Expected return on plan assets	(1,846)	(2,036)
Amortization of:
Prior service cost	2	3
Net actuarial (gains) losses recognized	692	560
Net Periodic Benefit Cost	1,667	1,532
Postretirement Benefits, U.S. Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	88	104
Amortization of:
Prior service cost	(22)	(22)
Net actuarial (gains) losses recognized	4	(14)
Net Periodic Benefit Cost	70	68
Postretirement Benefits, Non-U.S. Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	288	192
Interest cost	289	250
Amortization of:
Net actuarial (gains) losses recognized	114	18
Net Periodic Benefit Cost	$ 691	$ 460