Changes in Carrying Amount of Goodwill and Other Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Nov. 30, 2013	Nov. 30, 2012	Nov. 30, 2013	Nov. 30, 2012
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill, Beginning Balance			$ 3,109
Goodwill, Additions
Goodwill, Ending Balance	3,109		3,109
Goodwill and other intangible assets, Beginning balance			4,146
Goodwill and other intangible assets, Additions
Amortization	(41)	(41)	(82)	(82)
Goodwill and other intangible assets, Ending balance	4,064		4,064
Customer relationships, Ending Balance	544		544
Trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Trade name, Beginning balance			411
Trade name, Additions
Trade name, Ending balance	411		411
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Customer relationships, Beginning Balance			626
Customer relationships, Additions
Amortization			(82)
Customer relationships, Ending Balance	$ 544		$ 544