Retirement Related Benefit Plans' Impact on Income Before Income Taxes (Detail) (USD $) In Thousands	3 Months Ended
	Aug. 31, 2011	Aug. 31, 2010
U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 4,977	$ 4,239
Interest cost	3,827	3,434
Expected return on plan assets	(4,354)	(3,139)
Amortization of:
Prior service cost	88	90
Net actuarial (gains) losses recognized	2,127	1,980
Net Periodic Benefit Cost	6,665	6,604
Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	965	830
Interest cost	2,040	1,782
Expected return on plan assets	(2,036)	(1,655)
Amortization of:
Prior service cost	3	3
Net actuarial (gains) losses recognized	560	585
Net Periodic Benefit Cost	1,532	1,545
United States Postretirement Benefit Plans of US Entity, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Service cost		1
Interest cost	104	110
Amortization of:
Prior service cost	(22)	(21)
Net actuarial (gains) losses recognized	(14)	(48)
Net Periodic Benefit Cost	68	42
Foreign Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Service cost	192	169
Interest cost	250	213
Amortization of:
Net actuarial (gains) losses recognized	18	21
Net Periodic Benefit Cost	$ 460	$ 403