SEGMENT REPORTING - Segment Reporting Information by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information
Operating revenue	$ 141,786	$ 130,924	$ 392,296	$ 398,520
Operating income (loss)	4,434	(34)	3,122	5,870
Depreciation and amortization	9,896	9,652	29,941	27,595
Trucking
Segment Reporting Information
Operating revenue	96,732	93,354	277,652	283,963
USAT Logistics
Segment Reporting Information
Operating revenue	45,054	37,570	114,644	114,557
Operating Segments | Trucking
Segment Reporting Information
Operating revenue	97,383	93,587	280,005	284,965
Operating income (loss)	3,453	(278)	2,941	2,168
Depreciation and amortization	9,615	9,435	29,088	26,867
Operating Segments | USAT Logistics
Segment Reporting Information
Operating revenue	52,059	39,365	126,623	120,390
Operating income (loss)	981	244	181	3,702
Depreciation and amortization	281	217	853	728
Intersegment Eliminations
Segment Reporting Information
Operating revenue	(7,656)	(2,028)	(14,332)	(6,835)
Intersegment Eliminations | Trucking
Segment Reporting Information
Operating revenue	(651)	(233)	(2,353)	(1,002)
Intersegment Eliminations | USAT Logistics
Segment Reporting Information
Operating revenue	(7,005)	(1,795)	(11,979)	(5,833)
Foreign Countries | Operating Segments | Trucking
Segment Reporting Information
Operating revenue	$ 8,800	$ 9,500	$ 24,900	$ 28,500