Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015
Income Taxes [Line Items]
Tax benefits related to stock-based compensation credited to additional paid-in capital	$ 0	$ 0	$ 6,179
Tax benefits related to purchase of noncontrolling interest in dHybrid	539
Tax benefits (expense) related to defined benefit pension liability credited to other comprehensive income	(1,158)	1,175	1,914
Tax benefits (expenses) related to cash flow hedges credited to (deducted from) other comprehensive income	$ 1,700	$ (13,316)	$ 6,952
Effective tax rates upon inclusion of net earnings attributable to noncontrolling interests	26.70%	27.20%	22.80%
Minimum likelihood of tax benefits being recognized upon ultimate settlement	50.00%
Total unrecognized tax benefits	$ 2,975	$ 2,827	$ 3,530
Unrecognized tax benefits if recognized would affect tax rate attributable to controlling interest	2,225
Interest and penalties related to unrecognized tax benefits	307	538	$ 947
Undistributed earnings of consolidated foreign subsidiaries	241,000
Deferred tax liability would have been required if earnings were not permanently reinvested	12,000
Valuation allowance for deferred tax assets	12,987	$ 11,796
Settlement with Taxing Authority
Income Taxes [Line Items]
Liability for unrecognized tax benefit expected to be settled in the next 12 months	673
State and Local Jurisdiction
Income Taxes [Line Items]
Net operating loss carry forwards	8,470
Valuation allowance for deferred tax assets	$ 8,548
State and Local Jurisdiction | Earliest Tax Year
Income Taxes [Line Items]
Operating loss carryforwards, expiration date	May 31, 2018
State and Local Jurisdiction | Latest Tax Year
Income Taxes [Line Items]
Operating loss carryforwards, expiration date	May 31, 2037
Non - United States
Income Taxes [Line Items]
Net operating loss carry forwards	$ 4,786
Tax credit carry forwards	$ 3,206
Tax credit carryforward, expiration date	May 31, 2025
Valuation allowance for deferred tax assets	$ 4,439
Non - United States | Earliest Tax Year
Income Taxes [Line Items]
Operating loss carryforwards, expiration date	May 31, 2018
Non - United States | Latest Tax Year
Income Taxes [Line Items]
Operating loss carryforwards, expiration date	May 31, 2036