Retirement-Related Benefit Plans' Impact on Income Before Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Aug. 31, 2013	Aug. 31, 2012
Pension Benefits, U.S. Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 6,764	$ 6,488
Interest cost	4,510	4,060
Expected return on plan assets	(5,190)	(4,358)
Amortization of:
Prior service cost (credit)	83	87
Net actuarial (gains) losses recognized	3,306	4,222
Net Periodic Benefit Cost	9,473	10,499
Pension Benefits, Non-U.S. Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	1,109	1,050
Interest cost	1,800	1,769
Expected return on plan assets	(2,095)	(1,846)
Amortization of:
Prior service cost (credit)	1	2
Net actuarial (gains) losses recognized	623	692
Net Periodic Benefit Cost	1,438	1,667
Postretirement Benefits, U.S. Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	81	88
Amortization of:
Prior service cost (credit)	(22)	(22)
Net actuarial (gains) losses recognized	(29)	4
Net Periodic Benefit Cost	30	70
Postretirement Benefits, Non-U.S. Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	327	288
Interest cost	317	289
Amortization of:
Net actuarial (gains) losses recognized	133	114
Net Periodic Benefit Cost	$ 777	$ 691