Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	May. 31, 2015	May. 31, 2014	May. 31, 2013
Income Taxes [Line Items]
Tax benefits related to stock-based compensation credited to additional paid-in capital	$ 6,179,000	$ 7,115,000	$ 4,054,000
Tax benefits (expenses) related to defined benefit pension liability credited to (deducted from) other comprehensive income (loss) ["OCI"]	1,914,000	511,000	(1,415,000)
Tax benefits (expenses) related to cash flow hedges credited to (deducted from) OCI	$ 6,952,000	$ (1,039,000)	$ (763,000)
Effective tax rates upon inclusion of net earnings attributable to noncontrollng interests	22.80%	26.40%	32.00%
Minimum likelihood of tax benefits being recognized upon ultimate settlement	50.00%
Total unrecognized tax benefits	$ 3,530,000	$ 4,110,000	$ 3,705,000
Unrecognized tax benefits if recognized would affect tax rate attributable to controlling interest	2,401,000
Interest and penalties related to unrecognized tax benefits	947,000	1,049,000	$ 1,128,000
Liability for unrecognized tax benefit expected to be settled in the next 12 months	922,000
Undistributed earnings of consolidated foreign subsidiaries	205,000,000
Deferred tax liability would have been required if earnings were not permanently reinvested	13,000,000
Valuation allowance for deferred tax assets	13,036,000	$ 21,701,000
State and Local Jurisdiction
Income Taxes [Line Items]
Net operating loss carry forwards	$ 12,218,000
Net operating loss carry forwards, expiration dates	From fiscal 2016 to the fiscal year ending May 31, 2035
Valuation allowance for deferred tax assets	$ 11,607,000
Foreign
Income Taxes [Line Items]
Net operating loss carry forwards	$ 2,108,000
Net operating loss carry forwards, expiration dates	From fiscal 2018 to the fiscal year ending May 31, 2035
Tax credit carry forwards	$ 3,653,000
Tax credit carry forwards, expiration dates	That expires on May 31, 2025
Valuation allowance for deferred tax assets	$ 1,429,000