REVENUE EARNING EQUIPMENT, NET - Revenue Earning Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue Earning Equipment [Line Items]
Cost	$ 14,765,761	$ 16,172,017
Accumulated Depreciation	(5,988,746)	(5,744,353)
Net Book Value	$ 8,777,015	10,427,664
Trucks
Revenue Earning Equipment [Line Items]
Estimated useful life, minimum	3 years
Estimated useful life, maximum	7 years
Cost	$ 5,061,266	5,432,236
Accumulated Depreciation	(1,818,594)	(1,696,160)
Net Book Value	$ 3,242,672	3,736,076
Tractors
Revenue Earning Equipment [Line Items]
Estimated useful life, minimum	4 years
Estimated useful life, maximum	7 years 6 months
Cost	$ 7,013,595	7,859,371
Accumulated Depreciation	(2,853,591)	(2,670,234)
Net Book Value	$ 4,160,004	5,189,137
Trailers and other
Revenue Earning Equipment [Line Items]
Estimated useful life, minimum	9 years 6 months
Estimated useful life, maximum	12 years
Cost	$ 2,046,768	2,131,975
Accumulated Depreciation	(804,006)	(808,798)
Net Book Value	1,242,762	1,323,177
Held for sale
Revenue Earning Equipment [Line Items]
Cost	644,132	748,435
Accumulated Depreciation	(512,555)	(569,161)
Net Book Value	131,577	179,274
Assets held under finance leases
Revenue Earning Equipment [Line Items]
Cost	5,000	12,000
Accumulated Depreciation	$ (4,000)	$ (8,000)