Retirement Related Benefit Plans' Impact on Income Before Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Nov. 30, 2011	Nov. 30, 2010	Nov. 30, 2011	Nov. 30, 2010
Pension Benefits, U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 4,976	$ 4,240	$ 9,953	$ 8,479
Interest cost	3,827	3,435	7,654	6,869
Expected return on plan assets	(4,354)	(3,140)	(8,708)	(6,279)
Amortization of:
Prior service cost	88	89	176	179
Net actuarial (gains) losses recognized	2,128	1,979	4,255	3,959
Net Periodic Benefit Cost	6,665	6,603	13,330	13,207
Pension Benefits, Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	966	831	1,931	1,661
Interest cost	2,041	1,783	4,081	3,565
Expected return on plan assets	(2,037)	(1,656)	(4,073)	(3,311)
Amortization of:
Prior service cost	3	2	6	5
Net actuarial (gains) losses recognized	559	585	1,119	1,170
Net Periodic Benefit Cost	1,532	1,545	3,064	3,090
Postretirement Benefits, U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost		1		2
Interest cost	104	110	208	220
Amortization of:
Prior service cost	(21)	(22)	(43)	(43)
Net actuarial (gains) losses recognized	(15)	(47)	(29)	(95)
Net Periodic Benefit Cost	68	42	136	84
Postretirement Benefits, Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	192	170	384	339
Interest cost	249	213	499	426
Amortization of:
Net actuarial (gains) losses recognized	19	20	37	41
Net Periodic Benefit Cost	$ 460	$ 403	$ 920	$ 806