Goodwill and Other Intangible Assets - Summary of Intangible Assets (Detail) - USD ($) $ in Thousands	6 Months Ended
	Nov. 30, 2015	May. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 2,505	$ 2,505
Accumulated Amortization	(1,820)	(1,761)
Customer relationships, Net Carrying Amount	274
Net Carrying Amount	685	744
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Customer relationships, Gross Carrying Amount	2,094	2,094
Accumulated Amortization	(1,820)	(1,761)
Customer relationships, Net Carrying Amount	$ 274	333
Customer relationships | Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	3 years
Customer relationships | Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	8 years
Trade name
Finite-Lived Intangible Assets [Line Items]
Trade names, Gross Carrying Amount	$ 411	411
Trade names, Net Carrying Amount	$ 411	$ 411