INTANGIBLE ASSETS - Summary of Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 213,523	$ 213,413
Accumulated Amortization	(41,583)	(37,309)
Net Carrying Amount	171,940	176,104
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	174,805	174,742
Accumulated Amortization	(28,900)	(25,508)
Net Carrying Amount	145,905	149,234
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,417	5,397
Accumulated Amortization	(4,031)	(3,896)
Net Carrying Amount	1,386	1,501
Trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	24,644	24,624
Accumulated Amortization	(4,706)	(4,216)
Net Carrying Amount	19,938	20,408
Technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	7,817	7,812
Accumulated Amortization	(3,590)	(3,364)
Net Carrying Amount	4,227	4,448
Licenses
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	840	838
Accumulated Amortization	(356)	(325)
Net Carrying Amount	$ 484	$ 513