INTANGIBLE ASSETS - Summary of Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 191,254	$ 120,280
Accumulated Amortization	(24,403)	(21,161)
Net Carrying Amount	166,851	99,119
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	154,988	103,288
Accumulated Amortization	(15,396)	(12,995)
Net Carrying Amount	139,592	90,293
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	4,974	4,898
Accumulated Amortization	(3,614)	(3,468)
Net Carrying Amount	1,360	1,430
Trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	23,197	6,299
Accumulated Amortization	(2,466)	(1,940)
Net Carrying Amount	20,731	4,359
Technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	7,412	5,112
Accumulated Amortization	(2,694)	(2,541)
Net Carrying Amount	4,718	2,571
Licenses
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	683	683
Accumulated Amortization	(233)	(217)
Net Carrying Amount	$ 450	$ 466