OPERATING SEGMENT DATA - Revenue from customers (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenues
Revenues	$ 1,335,074	$ 829,213
Asset Based
Revenues
Revenues	675,518	529,724
ArcBest
Revenues
Revenues	591,722	250,241
FleetNet
Revenues
Revenues	66,983	48,434
Corporate and Other
Revenues
Revenues	851	814
Operating Segments | Asset Based
Revenues
Revenues	705,311	556,292
Operating Segments | ArcBest
Revenues
Revenues	595,284	252,336
Operating Segments | FleetNet
Revenues
Revenues	78,378	59,163
Intersegment revenues
Revenues
Revenues	(44,750)	(39,392)
Intersegment revenues | Asset Based
Revenues
Revenues	29,793	26,568
Intersegment revenues | ArcBest
Revenues
Revenues	3,562	2,095
Intersegment revenues | FleetNet
Revenues
Revenues	11,395	10,729
Other and eliminations
Revenues
Revenues	$ (43,899)	$ (38,578)