INTANGIBLE ASSETS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jan. 19, 2018	Dec. 31, 2017
Intangible assets subject to amortization
Gross Amount	$ 53,509		$ 53,509			$ 50,043
Accumulated amortization	(20,434)		(20,434)			(17,970)
Net Book Value	33,075		33,075			32,073
Intangible assets resulting from acquisition					$ 3,870
Amortization expense for intangible assets	872	$ 813	2,634	$ 2,405
Estimated amortization expense
Remainder of 2018	883		883
2019	3,499		3,499
2020	3,499		3,499
2021	3,241		3,241
2022	3,241		3,241
2023	3,159		3,159
Thereafter	15,553		15,553
Total estimated amortization expense	33,075		33,075
Customer lists
Intangible assets subject to amortization
Gross Amount	42,326		42,326			38,659
Accumulated amortization	(14,623)		(14,623)			(12,721)
Net Book Value	27,703		$ 27,703			25,938
Customer lists | Minimum
Intangible assets subject to amortization
Estimated Life			8 years
Customer lists | Maximum
Intangible assets subject to amortization
Estimated Life			17 years
Trade name
Intangible assets subject to amortization
Gross Amount	6,168		$ 6,168			6,213
Accumulated amortization	(3,165)		(3,165)			(2,798)
Net Book Value	3,003		$ 3,003			3,415
Trade name | Minimum
Intangible assets subject to amortization
Estimated Life			10 years
Trade name | Maximum
Intangible assets subject to amortization
Estimated Life			12 years
Design and technologies
Intangible assets subject to amortization
Gross Amount	4,991		$ 4,991			5,147
Accumulated amortization	(2,637)		(2,637)			(2,443)
Net Book Value	2,354		$ 2,354			2,704
Design and technologies | Minimum
Intangible assets subject to amortization
Estimated Life			10 years
Design and technologies | Maximum
Intangible assets subject to amortization
Estimated Life			12 years
Patents
Intangible assets subject to amortization
Gross Amount	24		$ 24			24
Accumulated amortization	(9)		(9)			(8)
Net Book Value	$ 15		$ 15			$ 16
Estimated Life			17 years