Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	May 31, 2012	May 31, 2011	May 31, 2010
Income Taxes [Line Items]
Tax benefits related to stock-based compensation credited to additional paid-in capital	$ 32,000	$ 835,000	$ 6,000
Tax benefits (expenses) related to defined benefit pension liability credited to (deducted from) other comprehensive income (loss) ["OCI"]	4,975,000	(760,000)	1,163,000
Tax benefits (expenses) related to cash flow hedges credited to (deducted from) OCI	318,000	563,000	854,000
Effective tax rates upon inclusion of net earnings attributable to noncontrollng interests	29.30%	32.00%	34.10%
Minimum likelihood of tax benefits being recognized upon ultimate settlement	50.00%
Total unrecognized tax benefits	4,410,000	5,381,000	5,933,000
Unrecognized tax benefits if recognized would affect tax rate attributable to controlling interest	2,862,000
Interest and penalties related to unrecognized tax benefits	1,219,000	1,184,000	1,232,000
Liability for unrecognized tax benefit expected to be settled in the next 12 months	470,000
Undistributed earnings of consolidated foreign subsidiaries	265,000,000
Deferred tax liability would have been required if earnings were not permanently reinvested	20,000,000
Valuation allowance for deferred tax assets	22,025,000	22,292,000
State and Local Jurisdiction
Income Taxes [Line Items]
Net operating loss carry forwards	18,102,000
Net operating loss carry forwards, expiration dates	From fiscal 2014 to the fiscal year ending May 31, 2032
Valuation allowance for deferred tax assets	17,230,000
Foreign
Income Taxes [Line Items]
Net operating loss carry forwards	2,222,000
Net operating loss carry forwards, expiration dates	From fiscal 2013 to the fiscal year ending May 31, 2019
Capital loss carry forwards	1,340,000
Capital loss carry forwards, expiration dates	No future expiration date
Tax credit carry forwards	1,032,000
Tax credit carry forwards, expiration dates	May 31, 2022
Valuation allowance for deferred tax assets	3,763,000
Federal
Income Taxes [Line Items]
Valuation allowance for deferred tax assets	$ 1,032,000