Components of Deferred Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	May 31, 2013	May 31, 2012
Deferred tax assets:
Goodwill and intangible assets		$ 300
Allowance for doubtful accounts	105	206
Deferred compensation and benefits	3,545	2,813
Net operating losses	1,110	871
Valuation allowance	(1,110)	(871)
Other	908	1,390
Net deferred tax asset	4,558	4,709
Deferred tax liabilities:
Accumulated depreciation	(51,948)	(56,532)
Deferred taxes on bargain purchase	(2,207)	(2,548)
Intangible asset	(143)
Net deferred tax liabilities	$ (49,740)	$ (54,371)