INTANGIBLE ASSETS - Summary of Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 214,302	$ 213,413
Accumulated Amortization	(50,143)	(37,309)
Net Carrying Amount	164,159	176,104
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	175,214	174,742
Accumulated Amortization	(35,554)	(25,508)
Net Carrying Amount	139,660	149,234
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,563	5,397
Accumulated Amortization	(4,388)	(3,896)
Net Carrying Amount	1,175	1,501
Trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	24,807	24,624
Accumulated Amortization	(5,714)	(4,216)
Net Carrying Amount	19,093	20,408
Technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	7,861	7,812
Accumulated Amortization	(4,060)	(3,364)
Net Carrying Amount	3,801	4,448
Licenses
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	857	838
Accumulated Amortization	(427)	(325)
Net Carrying Amount	$ 430	$ 513