Segment Information (Tables)

9 Months Ended

Sep. 30, 2019

Segment Reporting [Abstract]

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

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2019		2018		2019		2018
Revenues
Truckload	$	382,467	$	395,167	$	1,125,991	$	1,157,731
Brokerage		46,036		65,060		131,737		177,962
Total Operating Revenue	$	428,503	$	460,227	$	1,257,728	$	1,335,693
Operating Income (Loss)
Truckload	$	3,345	$	19,857	$	20,689	$	50,950
Brokerage		(63)		3,035		4,018		6,814
Total Operating Income	$	3,282	$	22,892	$	24,707	$	57,764

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

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2019		2018		2019		2018
Revenues
United States	$	428,503	$	446,822	$	1,255,356	$	1,295,900
Foreign countries
Mexico		—		13,405		2,372		39,793
Total	$	428,503	$	460,227	$	1,257,728	$	1,335,693