Description of Business and Summary of Significant Accounting Policies - Schedule of Disaggregation of Trucking Revenue from Contracts with Customers (ASC 606-10-50) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Total revenue	$ 88,846	$ 55,726
Trucking [Member]
Disaggregation of Revenue [Line Items]
Total revenue	53,952	55,406
Trucking [Member] | USPS Revenue [Member]
Disaggregation of Revenue [Line Items]
Total revenue	47,151	48,183
Trucking [Member] | Freight Revenue [Member]
Disaggregation of Revenue [Line Items]
Total revenue	6,561	6,575
Trucking [Member] | Other Revenue [Member]
Disaggregation of Revenue [Line Items]
Total revenue	$ 240	$ 648