Goodwill and Intangible Assets - Goodwill Roll Forward (Details) $ in Thousands  | 
9 Months Ended | 
|---|---|
| 
 Sep. 30, 2022  
USD ($) 
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| Goodwill [Roll Forward] | |
| Beginning balance | $ 266,752 | 
| Acquisition | 17,003 | 
| Acquisition adjustment | 4,741 | 
| Ending balance | 288,496 | 
| Goodwill accumulated impairment | 25,686 | 
| Tax deductible goodwill | 209,353 | 
| Expedited Freight | |
| Goodwill [Roll Forward] | |
| Beginning balance | 169,288 | 
| Acquisition | 0 | 
| Acquisition adjustment | 0 | 
| Ending balance | 169,288 | 
| Intermodal | |
| Goodwill [Roll Forward] | |
| Beginning balance | 97,464 | 
| Acquisition | 17,003 | 
| Acquisition adjustment | 4,741 | 
| Ending balance | $ 119,208 | 
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- Definition The amount of goodwill arising from a business combination that is expected to be deductible for tax purposes. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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- Definition Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination. Reference 1: http://www.xbrl.org/2003/role/exampleRef 
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- Definition Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available. 
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