Goodwill and Intangibles - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	May 31, 2013	May 31, 2012	May 31, 2011
Goodwill And Other Intangible Assets [Line Items]
Amortization expense of intangible assets	$ 164	$ 153	$ 184
EMT
Goodwill And Other Intangible Assets [Line Items]
Date of Acquisition	Aug. 24, 2011
Telogy LLC
Goodwill And Other Intangible Assets [Line Items]
Date of Acquisition	Mar. 31, 2010
Rush Computer Rentals, Inc.
Goodwill And Other Intangible Assets [Line Items]
Date of Acquisition	Jan. 31, 2006