Intangible Assets - Summary of Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	May. 31, 2015	May. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 120,280	$ 36,225	$ 36,211
Accumulated Amortization	(21,161)	(15,957)	(12,698)
Net Carrying Amount	99,119	20,268	23,513
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	103,288	22,612	22,424
Accumulated Amortization	(12,995)	(9,111)	(6,739)
Net Carrying Amount	90,293	13,501	15,685
Non-Compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	4,898	3,417	3,667
Accumulated Amortization	(3,468)	(3,363)	(3,430)
Net Carrying Amount	1,430	54	237
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	6,299	4,401	4,325
Accumulated Amortization	(1,940)	(1,074)	(717)
Net Carrying Amount	4,359	3,327	3,608
Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,112	5,112	5,112
Accumulated Amortization	(2,541)	(2,230)	(1,698)
Net Carrying Amount	2,571	2,882	3,414
Licenses [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	683	683	683
Accumulated Amortization	(217)	(179)	(114)
Net Carrying Amount	$ 466	$ 504	$ 569