Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	May 31, 2016	May 31, 2015	May 31, 2014
Income Taxes [Line Items]
Tax benefits related to stock-based compensation credited to additional paid-in capital	$ 0	$ 6,179,000	$ 7,115,000
Tax benefits related to defined benefit pension liability credited to other comprehensive income	1,175,000	1,914,000	511,000
Tax benefits (expenses) related to cash flow hedges credited to (deducted from) other comprehensive income	$ (13,316,000)	$ 6,952,000	$ (1,039,000)
Effective tax rates upon inclusion of net earnings attributable to noncontrolling interests	27.20%	22.80%	26.40%
Minimum likelihood of tax benefits being recognized upon ultimate settlement	50.00%
Total unrecognized tax benefits	$ 2,827,000	$ 3,530,000	$ 4,110,000
Unrecognized tax benefits if recognized would affect tax rate attributable to controlling interest	2,035,000
Interest and penalties related to unrecognized tax benefits	538,000	947,000	$ 1,049,000
Undistributed earnings of consolidated foreign subsidiaries	225,000,000
Deferred tax liability would have been required if earnings were not permanently reinvested	15,000,000
Valuation allowance for deferred tax assets	11,796,000	$ 13,036,000
Settlement with Taxing Authority
Income Taxes [Line Items]
Liability for unrecognized tax benefit expected to be settled in the next 12 months	404,000
State and Local Jurisdiction
Income Taxes [Line Items]
Net operating loss carry forwards	9,615,000
Valuation allowance for deferred tax assets	$ 9,395,000
State and Local Jurisdiction | Earliest Tax Year
Income Taxes [Line Items]
Operating loss carryforwards, expiration date	May 31, 2017
State and Local Jurisdiction | Latest Tax Year
Income Taxes [Line Items]
Operating loss carryforwards, expiration date	May 31, 2036
Non - United States
Income Taxes [Line Items]
Net operating loss carry forwards	$ 3,141,000
Tax credit carry forwards	3,127,000
Valuation allowance for deferred tax assets	$ 2,401,000
Non - United States | Earliest Tax Year
Income Taxes [Line Items]
Operating loss carryforwards, expiration date	May 31, 2018
Tax credit carryforward, expiration date	May 31, 2025
Non - United States | Latest Tax Year
Income Taxes [Line Items]
Operating loss carryforwards, expiration date	May 31, 2036
Tax credit carryforward, expiration date	May 31, 2026