OPERATING SEGMENT DATA - Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenues
Revenues	$ 1,392,929	$ 948,973	$ 2,728,003	$ 1,778,186
Asset Based
Revenues
Revenues	788,973	630,145	1,464,491	1,159,869
ArcBest
Revenues
Revenues	538,780	268,038	1,130,502	518,279
FleetNet
Revenues
Revenues	68,204	49,951	135,187	98,385
Operating Segments | Asset Based
Revenues
Revenues	802,622	652,832	1,507,933	1,209,124
Operating Segments | ArcBest
Revenues
Revenues	549,655	270,748	1,144,939	523,084
Operating Segments | FleetNet
Revenues
Revenues	82,132	59,547	160,510	118,710
Other and eliminations
Revenues
Revenues	$ (41,480)	$ (34,154)	$ (85,379)	$ (72,732)