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Divesture of Xpress Internacional (Details) $ in Thousands		3 Months Ended	12 Months Ended
Divesture of Xpress Internacional (Details) $ in Thousands	Jan. 17, 2019 USD ($) item	Dec. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of tractors sold \| item	110
Fair value of assets held for sale				$ 5,200
Impairment of assets in disposal group			$ 6,793	12,497
Impairment of assets held for sale				(10,693)
Tractors [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Fair value of assets held for sale	$ 2,500	$ 1,700	1,700
Xpress Internacional \| Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash proceeds	4,500
Note received in disposal	6,000		1,600
Contingent consideration received in disposal	$ 2,500
Subsequent gain			$ 800
Xpress Internacional \| Disposal Group, Held-for-sale, Not Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of assets in disposal group				$ 11,629
Impairment of assets held for sale		$ 10,700
Xpress Internacional
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership interest, as a percent	95.00%