Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Contract with Customer, Asset, after Allowance for Credit Loss	$ 1,700		$ 1,700		$ 1,300
Operating Revenue	187,821	$ 154,128	339,097	$ 306,530
Accessorial and other revenues	4,300	2,800	7,500	5,900
fuel surcharge [Member]
Disaggregation of Revenue [Line Items]
Fuel surcharge revenue	$ 36,400	$ 19,100	$ 60,300	$ 35,900