SEGMENT REPORTING - Segment Reporting Information by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information
Operating revenue	$ 123,737	$ 133,622	$ 250,510	$ 267,596
Operating income (loss)	1,000	1,983	(1,312)	5,904
Depreciation and amortization	10,034	9,125	20,045	17,943
Trucking
Segment Reporting Information
Operating revenue	87,920	96,069	180,921	190,609
USAT Logistics
Segment Reporting Information
Operating revenue	35,817	37,553	69,589	76,987
Operating Segments | Trucking
Segment Reporting Information
Operating revenue	88,627	96,476	182,622	191,378
Operating income (loss)	1,176	837	(511)	2,445
Depreciation and amortization	9,697	8,853	19,473	17,432
Operating Segments | USAT Logistics
Segment Reporting Information
Operating revenue	38,738	39,575	74,562	81,025
Operating income (loss)	(176)	1,146	(801)	3,459
Depreciation and amortization	337	272	572	511
Intersegment Eliminations
Segment Reporting Information
Operating revenue	(3,628)	(2,429)	(6,674)	(4,807)
Intersegment Eliminations | Trucking
Segment Reporting Information
Operating revenue	(707)	(407)	(1,701)	(769)
Intersegment Eliminations | USAT Logistics
Segment Reporting Information
Operating revenue	(2,921)	(2,022)	(4,973)	(4,038)
Foreign countries | Operating Segments | Trucking
Segment Reporting Information
Operating revenue	$ 7,500	$ 9,400	$ 16,100	$ 19,000