Summary of Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Feb. 28, 2014	May 31, 2013
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 36,105	$ 34,989
Accumulated Amortization	(11,715)	(9,039)
Net Carrying Amount	24,390	25,950
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	22,355	21,418
Accumulated Amortization	(6,059)	(4,168)
Net Carrying Amount	16,296	17,250
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	3,630	3,701
Accumulated Amortization	(3,352)	(3,232)
Net Carrying Amount	278	469
Trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	4,325	4,075
Accumulated Amortization	(641)	(424)
Net Carrying Amount	3,684	3,651
Technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,112	5,112
Accumulated Amortization	(1,565)	(1,166)
Net Carrying Amount	3,547	3,946
Licenses
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	683	683
Accumulated Amortization	(98)	(49)
Net Carrying Amount	$ 585	$ 634