Segment Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments	2
Revenues
Total Operating Revenue	$ 432,568	$ 415,363
Operating Income
Total Operating Income (Loss)	(3,668)	12,638
Truckload Segment [Member]
Revenues
Total Operating Revenue	382,092	369,119
Operating Income
Total Operating Income (Loss)	1,200	9,842
Brokerage Segment [Member]
Revenues
Total Operating Revenue	50,476	46,244
Operating Income
Total Operating Income (Loss)	$ (4,868)	$ 2,796