Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	May. 31, 2015	May. 31, 2014	May. 31, 2013
Deferred tax assets:
Allowance for doubtful accounts	$ 113	$ 198
Deferred compensation and benefits	4,588	4,547
Net operating losses	398	254
Valuation allowance	(398)	(254)	$ (1,110)
Other	1,890	1,791
Net deferred tax asset	6,591	6,536
Deferred tax liabilities:
Accumulated depreciation	(42,505)	(46,169)
Deferred taxes on bargain purchase	(1,583)	(2,027)
Intangible asset	(155)	(152)
Net deferred tax liabilities	(37,652)	(41,812)
Undistributed Earnings of Foreign Subsidiaries	$ 7,574	$ 6,303	$ 1,833