REPORTABLE SEGMENTS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	$ 1,454.1	$ 1,737.0	$ 1,613.1
Operating income (loss)	35.4	(312.1)	21.9
Depreciation	91.1	132.2	114.4
Amortization of intangible assets	7.2	14.3	16.7
Impairment	15.4	312.8	13.9
Restructuring	9.5	8.4
Non-cash operating lease expense	(8.0)	27.2
Interest expense	44.9	50.4	45.5
Income (loss) before income tax	6.0	(362.0)	(21.1)
Total assets	1,126.9	1,140.6	1,390.9
Cash capital expenditures	95.5	94.7	156.3
Company freight
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	676.8	804.6	721.7
Owner operator freight
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	408.9	455.3	440.5
Brokerage
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	234.3	294.7	266.4
Logistics
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	37.4	47.5	42.8
Fuel surcharge
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	96.7	134.9	141.7
Corporate/Eliminations
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	(18.5)	(21.7)	(14.0)
Operating income (loss)	(50.5)	(59.0)	(34.1)
Depreciation	0.9	0.7	0.2
Restructuring	0.1	2.8
Non-cash operating lease expense		0.4
Interest expense	24.0	26.8	25.6
Income (loss) before income tax	(33.2)	(32.3)	(27.8)
Total assets	204.3	109.4	41.9
Cash capital expenditures	7.6	1.6	2.1
Corporate/Eliminations | Company freight
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	(10.0)	(13.9)	(8.8)
Corporate/Eliminations | Owner operator freight
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	(5.7)	(5.9)	(2.8)
Corporate/Eliminations | Brokerage
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	(1.6)		(0.9)
Corporate/Eliminations | Logistics
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue		(0.1)	(0.1)
Corporate/Eliminations | Fuel surcharge
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	(1.2)	(1.8)	(1.4)
Flatbed
Segment Reporting Information, Profit (Loss) [Abstract]
Intersegment revenues and expenses	6.5	9.5	5.1
Insurance costs included in the corporate segment		3.6
Flatbed | Consolidated
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	578.9	663.0	662.0
Operating income (loss)	32.6	(94.4)	32.9
Depreciation	35.1	46.5	29.9
Amortization of intangible assets	3.2	5.3	6.2
Impairment	2.0	116.7
Restructuring	0.6	1.7
Non-cash operating lease expense	(0.3)	10.6
Interest expense	9.5	10.7	8.6
Income (loss) before income tax	7.2	(126.1)	13.8
Total assets	326.1	348.1	464.8
Cash capital expenditures	30.3	38.3	38.2
Flatbed | Consolidated | Company freight
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	191.2	215.3	206.2
Flatbed | Consolidated | Owner operator freight
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	262.1	275.7	271.5
Flatbed | Consolidated | Brokerage
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	70.3	93.9	104.2
Flatbed | Consolidated | Logistics
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	2.9	2.8	3.0
Flatbed | Consolidated | Fuel surcharge
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	52.4	75.3	77.1
Specialized
Segment Reporting Information, Profit (Loss) [Abstract]
Intersegment revenues and expenses	12.0	11.5	8.9
Insurance costs included in the corporate segment		11.2
Specialized | Consolidated
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	893.7	1,095.7	965.1
Operating income (loss)	53.3	(158.7)	23.1
Depreciation	55.1	85.0	84.3
Amortization of intangible assets	4.0	9.0	10.5
Impairment	13.4	196.1	13.9
Restructuring	8.8	3.9
Non-cash operating lease expense	(7.7)	16.2
Interest expense	11.4	12.9	11.3
Income (loss) before income tax	32.0	(203.6)	(7.1)
Total assets	596.5	683.1	884.2
Cash capital expenditures	57.6	54.8	116.0
Specialized | Consolidated | Company freight
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	495.6	603.2	524.3
Specialized | Consolidated | Owner operator freight
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	152.5	185.5	171.8
Specialized | Consolidated | Brokerage
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	165.6	200.8	163.1
Specialized | Consolidated | Logistics
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	34.5	44.8	39.9
Specialized | Consolidated | Fuel surcharge
Segment Reporting Information, Profit (Loss) [Abstract]
Total revenue	$ 45.5	$ 61.4	$ 66.0