Tax Effects of Temporary Differences that Give Rise to Significant Portions of Deferred Tax Assets and Deferred Tax Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	May 31, 2014	May 31, 2013
Deferred tax assets:
Accrued compensation and benefits	$ 3,625	$ 3,819
Receivables	1,180	1,686
Inventory	560	598
Stock options	3,299	3,671
Foreign currency translation and other equity adjustments	1,242
Net operating loss carry forwards	352	175
Other	2,675	1,158
Deferred tax assets	12,933	11,107
Less: Valuation allowance	(479)	(65)
Deferred tax assets, net	12,454	11,042
Deferred tax liabilities:
Property, plant and equipment	(11,248)	(12,548)
Goodwill and intangible costs	(6,619)	(5,308)
Foreign currency translation and other equity adjustments		(261)
Unremitted earnings of foreign subsidiaries	(1,185)	(1,973)
Prepaids	(1,318)	(1,263)
Other	(588)	(718)
Deferred tax liabilities	(20,958)	(22,071)
Net deferred tax liability	$ (8,504)	$ (11,029)