OPERATING SEGMENT DATA - Operating Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
OPERATING EXPENSES
Salaries, wages, and benefits	$ 451,824	$ 397,116	$ 1,321,871	$ 1,145,657
Fuel, supplies, and expenses	112,834	82,051	331,759	235,221
Depreciation and amortization	34,707	30,359	104,860	90,995
Gain on sale of subsidiary			(402)	(6,923)
Gain on sale of property and equipment			(9,759)	(8,389)
Other	40,074	36,811	118,922	89,062
Total consolidated operating expenses	1,236,070	929,096	3,731,799	2,600,792
ArcBest
OPERATING EXPENSES
Gain on sale of subsidiary				(6,900)
Operating Segments | Asset Based
OPERATING EXPENSES
Salaries, wages, and benefits	332,359	305,839	973,924	893,903
Fuel, supplies, and expenses	97,279	66,947	281,406	192,477
Operating taxes and licenses	13,089	12,426	38,405	36,977
Insurance	13,180	10,175	35,808	28,568
Communications and utilities	4,794	4,559	14,129	14,192
Depreciation and amortization	24,117	23,233	72,885	70,025
Rents and purchased transportation	123,714	95,855	348,249	266,525
Shared services	72,286	71,017	215,020	196,255
Gain on sale of property and equipment	(5,910)		(9,975)	(8,624)
Innovative technology costs	6,068	6,903	20,982	21,303
Other	1,243	592	2,629	1,103
Total consolidated operating expenses	682,219	597,546	1,993,462	1,712,704
Operating Segments | Asset Based | Land and structures
OPERATING EXPENSES
Gain on sale of property and equipment				(8,600)
Noncash gain on a like-kind property exchange of a service center	4,300		4,300
Operating Segments | ArcBest
OPERATING EXPENSES
Purchased transportation	425,567	256,900	1,382,107	694,498
Supplies and expenses	4,378	2,741	11,907	7,785
Depreciation and amortization	5,072	2,352	15,720	7,104
Shared services	56,371	31,048	164,554	86,198
Gain on sale of subsidiary			(402)	(6,923)
Other	8,463	1,984	22,309	6,055
Total consolidated operating expenses	499,851	295,025	1,596,195	794,717
Operating Segments | FleetNet
OPERATING EXPENSES
Total consolidated operating expenses	88,395	65,245	245,596	181,794
Other and eliminations
OPERATING EXPENSES
Total consolidated operating expenses	$ (34,395)	$ (28,720)	$ (103,454)	$ (88,423)