Goodwill and Intangibles - Changes in Carrying Amount of Goodwill and Other Intangible Assets (Detail) - USD ($) $ in Thousands	3 Months Ended
	Aug. 31, 2015	Aug. 31, 2014	Aug. 31, 2015
Goodwill [Roll Forward]
Balance as of June 1, 2015 (net of amortization)	$ 3,109
Additions	0
Balance as of August 31, 2015	3,109
Customer Relationships [Roll Forward]
Amortization	(29)	$ (41)
Balance as of August 31, 2015			$ 304
Goodwill and Other Intangible Assets [Roll Forward]
Balance as of June 1, 2015 (net of amortization)	3,853
Additions	0
Amortization	(29)	$ (41)
Balance as of August 31, 2015	3,824
Customer relationships
Customer Relationships [Roll Forward]
Balance as of June 1, 2015 (net of amortization)	333
Additions	0
Amortization	(29)
Balance as of August 31, 2015	333		$ 304
Goodwill and Other Intangible Assets [Roll Forward]
Amortization	(29)
Trade name
Trade Name [Roll Forward]
Balance as of June 1, 2015 (net of amortization)	411
Additions	0
Balance as of August 31, 2015	$ 411