OPERATING SEGMENT DATA - Revenue from customers (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues
Revenues	$ 3,980,067	$ 2,940,163	$ 2,988,310
Asset Based
Revenues
Revenues	2,470,529	1,998,549	2,077,287
ArcBest
Revenues
Revenues	1,291,679	770,560	731,366
FleetNet
Revenues
Revenues	213,882	166,654	175,055
Corporate and Other
Revenues
Revenues	3,977	4,400	4,602
Operating Segments | Asset Based
Revenues
Revenues	2,573,773	2,092,031	2,144,679
Operating Segments | ArcBest
Revenues
Revenues	1,300,626	779,115	738,392
Operating Segments | FleetNet
Revenues
Revenues	254,087	205,049	211,738
Intersegment revenues
Revenues
Revenues	(152,396)	(140,432)	(111,101)
Intersegment revenues | Asset Based
Revenues
Revenues	103,244	93,482	67,392
Intersegment revenues | ArcBest
Revenues
Revenues	8,947	8,555	7,026
Intersegment revenues | FleetNet
Revenues
Revenues	40,205	38,395	36,683
Other and eliminations
Revenues
Revenues	$ (148,419)	$ (136,032)	$ (106,499)