Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	May 31, 2014	May 31, 2013	May 31, 2012
Income Taxes [Line Items]
Tax benefits related to stock-based compensation credited to additional paid-in capital	$ 7,115,000	$ 4,054,000	$ 32,000
Tax benefits (expenses) related to defined benefit pension liability credited to (deducted from) other comprehensive income (loss) ["OCI"]	511,000	(1,415,000)	4,975,000
Tax benefits (expenses) related to cash flow hedges credited to (deducted from) OCI	(1,039,000)	(763,000)	318,000
Effective tax rates upon inclusion of net earnings attributable to noncontrollng interests	26.40%	32.00%	29.30%
Minimum likelihood of tax benefits being recognized upon ultimate settlement	50.00%
Total unrecognized tax benefits	4,110,000	3,705,000	4,410,000
Unrecognized tax benefits if recognized would affect tax rate attributable to controlling interest	2,672,000
Interest and penalties related to unrecognized tax benefits	1,049,000	1,128,000	1,219,000
Liability for unrecognized tax benefit expected to be settled in the next 12 months	832,000
Undistributed earnings of consolidated foreign subsidiaries	237,000,000
Deferred tax liability would have been required if earnings were not permanently reinvested	22,000,000
Valuation allowance for deferred tax assets	21,701,000	21,863,000
TWB | Joint Venture Transactions
Income Taxes [Line Items]
Percentage of additional interest acquired by the company	10.00%
One-time tax adjustment	7,100,000
State and Local Jurisdiction
Income Taxes [Line Items]
Net operating loss carry forwards	14,614,000
Net operating loss carry forwards, expiration dates	From fiscal 2015 to the fiscal year ending May 31, 2034
Valuation allowance for deferred tax assets	12,754,000
Foreign
Income Taxes [Line Items]
Net operating loss carry forwards	3,423,000
Net operating loss carry forwards, expiration dates	From fiscal 2015 to the fiscal year ending May 31, 2022
Capital loss carry forwards	1,265,000
Capital loss carry forwards, expiration dates	No future expiration date
Valuation allowance for deferred tax assets	8,947,000
Foreign Investment Enterprises
Income Taxes [Line Items]
Tax credit carry forwards	$ 203,000
Tax credit carry forwards, expiration dates	That expire from fiscal 2015 to the fiscal year ending May 31, 2017