OPERATING SEGMENT DATA (BalSh) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
OPERATING SEGMENT DATA
ASSETS	$ 1,309,992	$ 1,262,909	$ 1,127,622
CAPITAL EXPENDITURES, GROSS	151,637	159,017	90,808
DEPRECIATION AND AMORTIZATION EXPENSE	103,053	93,042	86,222
Amortization of intangibles	4,239	4,002	4,352
Operating Segments | Asset-Based
OPERATING SEGMENT DATA
ASSETS	791,117	694,059	621,734
CAPITAL EXPENDITURES, GROSS	110,170	122,542	78,766
DEPRECIATION AND AMORTIZATION EXPENSE	83,570	74,765	68,752
Assets acquired through notes payable and capital leases	83,400	80,600	55,300
Operating Segments | ArcBest
OPERATING SEGMENT DATA
ASSETS	330,345	315,859	275,426
CAPITAL EXPENDITURES, GROSS	6,154	24,219	6,996
DEPRECIATION AND AMORTIZATION EXPENSE	14,151	13,375	13,329
Amortization of intangibles	4,000	3,700	4,200
Operating Segments | FleetNet
OPERATING SEGMENT DATA
ASSETS	21,627	21,958	23,532
CAPITAL EXPENDITURES, GROSS	403	1,007	550
DEPRECIATION AND AMORTIZATION EXPENSE	1,209	1,119	961
Amortization of intangibles	300	300	200
Other and eliminations
OPERATING SEGMENT DATA
ASSETS	166,903	231,033	206,930
CAPITAL EXPENDITURES, GROSS	34,910	11,249	4,496
DEPRECIATION AND AMORTIZATION EXPENSE	$ 4,123	$ 3,783	$ 3,180