Segment Information (Tables)

12 Months Ended

Dec. 31, 2019

Segment Reporting [Abstract]

Reconciliation of Revenue from Segments to Consolidated [Table Text Block]

	Year Ended December 31,
	2019		2018		2017
Revenues
Truckload	$	1,521,494	$	1,562,098	$	1,382,167
Brokerage		185,867		242,817		173,218
Total Operating Revenue	$	1,707,361	$	1,804,915	$	1,555,385
Operating Income
Truckload	$	24,071	$	69,088	$	25,200
Brokerage		1,999		9,818		3,408
Total Operating Income	$	26,070	$	78,906	$	28,608

Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Table Text Block]

	Year Ended December 31,
	2019		2018		2017
Revenues
United States	$	1,704,989	$	1,751,556	$	1,504,926
Foreign countries
Mexico		2,372		53,359		50,459
Total	$	1,707,361	$	1,804,915	$	1,555,385