Short-Term Borrowings and Credit Lines - Notes Payable to Banks and Interest Bearing Accounts Payable to Sojitz Corporation of America (Detail) - USD ($)		May. 31, 2015	May. 31, 2014
Short-term Debt [Line Items]
Commercial Paper		$ 0	$ 0
Notes payable:
TOTAL NOTES PAYABLE		74,000,000	167,000,000
Interest-bearing accounts payable:
Line of credit facility, amount outstanding			0
Notes Payable
Notes payable:
TOTAL NOTES PAYABLE		74,000,000	167,000,000
UNITED STATES | Notes Payable
Notes payable:
TOTAL NOTES PAYABLE		$ 0	$ 0
Notes payable - interest rate	[1]	0.00%	0.00%
Non-U.S. operations | Notes Payable
Notes payable:
TOTAL NOTES PAYABLE		$ 74,000,000	$ 167,000,000
Notes payable - interest rate	[1]	12.39%	10.04%
Sojitz America
Interest-bearing accounts payable:
Sojitz America		$ 78,000,000	$ 60,000,000
Sojitz America - interest rate		0.98%	0.94%

[1] Weighted average interest rate includes non-interest bearing overdrafts.