GOODWILL AND INTANGIBLE ASSETS - Other Intangibles (Details 1) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Intangible Assets	$ 104,870		$ 104,870		$ 94,660
Accumulated Amortization	(27,329)		(27,329)		(23,007)
Intangible Assets, net	77,541		77,541		71,653
Foreign currency translation adjustment, accumulated adjustment	(317)		(317)
Foreign currency translation adjustment, Intangible asset, net	317		317
Amortization of intangible assets	1,765	$ 1,494	4,649	$ 4,542
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2017	6,300		6,300
2018	6,500		6,500
2019	6,400		6,400
2020	5,600		5,600
2021	5,100		5,100
Trade names
Indefinite-Lived Intangible Assets (Excluding Goodwill) [Abstract]
Indefinite lived intangible assets	34,780		34,780		30,100
Non-competition agreements
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Intangible Assets	10,900		10,900		8,350
Accumulated Amortization	(5,175)		(5,175)		(3,929)
Intangible Assets, net	5,725		$ 5,725		4,421
Weighted average remaining useful lives			2 years 7 months 17 days
Customer relationships
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Intangible Assets	59,190		$ 59,190		56,210
Accumulated Amortization	(22,471)		(22,471)		(19,078)
Intangible Assets, net	36,719		$ 36,719		$ 37,132
Weighted average remaining useful lives			7 years 9 months 22 days
Flatbed
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Amortization of intangible assets	437	489	$ 1,310	1,468
Specialized
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Amortization of intangible assets	$ 1,328	$ 1,005	$ 3,339	$ 3,074