INTANGIBLE ASSETS - Summary of Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 195,707	$ 120,280
Accumulated Amortization	(28,511)	(21,161)
Net Carrying Amount	167,196	99,119
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	156,840	103,288
Accumulated Amortization	(18,368)	(12,995)
Net Carrying Amount	138,472	90,293
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,477	4,898
Accumulated Amortization	(3,711)	(3,468)
Net Carrying Amount	1,766	1,430
Trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	24,710	6,299
Accumulated Amortization	(3,249)	(1,940)
Net Carrying Amount	21,461	4,359
Technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	7,834	5,112
Accumulated Amortization	(2,918)	(2,541)
Net Carrying Amount	4,916	2,571
Licenses
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	846	683
Accumulated Amortization	(265)	(217)
Net Carrying Amount	$ 581	$ 466