REPORTABLE SEGMENTS (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	$ 376,899	$ 197,323	$ 704,480	$ 357,757
Operating income (loss)	8,508	4,464	16,265	3,616
Depreciation	25,527	16,196	48,815	31,069
Amortization of intangible assets	6,239	1,442	8,133	2,884
Interest expense	11,070	6,544	21,407	12,440
Income (loss) before provision for income taxes	(1,061)	(1,923)	(2,241)	(12,438)
Total assets	1,324,102	694,995	1,324,102	694,995	$ 1,125,668
Capital expenditures	23,543	5,312	31,123	6,806
Operating Segments
Segment Reporting Information, Profit (Loss) [Abstract]
Intersegment revenues and expenses			2,100	1,700
Corporate/Eliminations
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	(3,638)	(1,560)	(5,953)	(3,103)
Operating income (loss)	(7,867)	(6,447)	(12,218)	(12,181)
Depreciation	25	39	56	78
Interest expense	6,384	2,984	12,368	5,260
Income (loss) before provision for income taxes	(13,048)	(9,398)	(23,049)	(21,109)
Total assets	57,301	35,590	57,301	35,590
Capital expenditures	219	24	410	48
Flatbed | Operating Segments
Segment Reporting Information, Profit (Loss) [Abstract]
Intersegment revenues and expenses	1,300	700
Total revenue	162,179	86,898	307,187	168,202
Operating income (loss)	9,269	6,322	16,232	10,201
Depreciation	6,726	6,823	13,669	13,905
Amortization of intangible assets	2,508	437	2,945	874
Interest expense	1,957	1,722	3,805	3,486
Income (loss) before provision for income taxes	7,436	4,623	12,632	6,728
Total assets	409,537	276,726	409,537	276,726
Capital expenditures	1,865	138	2,396	224
Specialized | Operating Segments
Segment Reporting Information, Profit (Loss) [Abstract]
Intersegment revenues and expenses	2,400	800	3,900	1,400
Total revenue	218,358	111,985	403,246	192,658
Operating income (loss)	7,106	4,589	12,251	5,596
Depreciation	18,776	9,334	35,090	17,086
Amortization of intangible assets	3,731	1,005	5,188	2,010
Interest expense	2,729	1,838	5,234	3,694
Income (loss) before provision for income taxes	4,551	2,852	8,176	1,943
Total assets	857,264	382,679	857,264	382,679
Capital expenditures	$ 21,459	$ 5,150	$ 28,317	$ 6,534