Intangible Assets - Summary of Intangible Assets (Detail) - USD ($) $ in Thousands	Aug. 31, 2015	May. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 115,697	$ 36,225
Accumulated Amortization	(17,961)	(15,957)
Net Carrying Amount	97,736	20,268
Customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	99,164	22,612
Accumulated Amortization	(10,636)	(9,111)
Net Carrying Amount	88,528	13,501
Non-compete agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,036	3,417
Accumulated Amortization	(3,380)	(3,363)
Net Carrying Amount	1,656	54
Trade names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,702	4,401
Accumulated Amortization	(1,387)	(1,074)
Net Carrying Amount	4,315	3,327
Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,112	5,112
Accumulated Amortization	(2,363)	(2,230)
Net Carrying Amount	2,749	2,882
Licenses [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	683	683
Accumulated Amortization	(195)	(179)
Net Carrying Amount	$ 488	$ 504