Intangible Assets Subject to Amortization and Amortization Expense (Detail) (USD $) In Thousands, unless otherwise specified	Feb. 28, 2015	May 31, 2014
Finite-Lived Intangible Assets [Line Items]
Finite Lived Intangible Assets Gross	$ 1,027	$ 1,053
Finite Lived Intangible Assets Accumulated Amortization	262	210
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Finite Lived Intangible Assets Gross	29	29
Finite Lived Intangible Assets Accumulated Amortization	26	18
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite Lived Intangible Assets Gross	951	977
Finite Lived Intangible Assets Accumulated Amortization	216	178
Noncompete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Finite Lived Intangible Assets Gross	47	47
Finite Lived Intangible Assets Accumulated Amortization	$ 20	$ 14