OPERATING SEGMENT DATA (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
REVENUES
Revenues	$ 713,923	$ 709,380	$ 2,012,005	$ 2,018,771
OPERATING EXPENSES
Salaries, wages, and benefits	345,091	334,144	1,009,654	973,570
Rents, purchased transportation, and other costs of services	218,906	209,744	601,345	588,329
Fuel, supplies, and expenses	69,508	77,067	204,134	231,097
Depreciation and amortization	25,793	23,373	76,692	68,221
Gain on sale of property and equipment			(2,581)	(1,691)
Pension settlement expense	800	800	2,267	2,478
Other	34,255	31,614	92,421	89,371
Total consolidated operating expenses	693,553	675,942	1,984,246	1,950,588
OPERATING INCOME
OPERATING INCOME	20,370	33,438	27,759	68,183
OTHER INCOME (COSTS)
Interest and dividend income	390	378	1,178	882
Interest and other related financing costs	(1,296)	(1,157)	(3,774)	(3,183)
Other, net	1,091	(613)	2,028	(15)
TOTAL OTHER INCOME (COSTS)	185	(1,392)	(568)	(2,316)
INCOME BEFORE INCOME TAXES	20,555	32,046	27,191	65,867
ASSETS
ASSETS	1,320,868		1,320,868		$ 1,262,909
Freight Transportation (ABF Freight)
OPERATING EXPENSES
Pension settlement expense	600	600	1,700	1,900
Operating Segments | Freight Transportation (ABF Freight)
REVENUES
Revenues	509,452	511,346	1,435,691	1,456,924
OPERATING EXPENSES
Salaries, wages, and benefits	312,458	304,865	912,758	884,875
Fuel, supplies, and expenses	71,774	77,708	210,742	236,381
Operating taxes and licenses	12,312	12,444	36,446	36,762
Insurance	8,487	8,288	22,613	20,340
Communications and utilities	4,608	3,808	13,259	11,559
Depreciation and amortization	20,753	18,841	62,056	54,528
Rents and purchased transportation	58,350	56,920	145,846	151,144
Gain on sale of property and equipment	(81)	(565)	(2,450)	(1,403)
Pension settlement expense	604	572	1,705	1,860
Other	2,137	1,888	6,293	6,167
Total consolidated operating expenses	491,402	484,769	1,409,268	1,402,213
OPERATING INCOME
OPERATING INCOME	18,050	26,577	26,423	54,711
ASSETS
ASSETS	763,385		763,385		694,059
Operating Segments | Premium Logistics (Panther)
REVENUES
Revenues	75,365	73,583	211,148	229,146
OPERATING EXPENSES
Purchased transportation	54,586	54,015	155,444	168,569
Depreciation and amortization	2,860	2,773	8,565	8,636
Salaries, benefits, insurance, and other	13,946	14,062	41,808	43,174
Total consolidated operating expenses	71,392	70,850	205,817	220,379
OPERATING INCOME
OPERATING INCOME	3,973	2,733	5,331	8,767
ASSETS
ASSETS	215,659		215,659		216,075
Operating Segments | Transportation Management (ABF Logistics)
REVENUES
Revenues	72,442	49,270	207,344	147,061
OPERATING EXPENSES
Total consolidated operating expenses	72,032	47,478	205,772	142,686
OPERATING INCOME
OPERATING INCOME	410	1,792	1,572	4,375
ASSETS
ASSETS	113,079		113,079		75,023
Operating Segments | Emergency & Preventative Maintenance (FleetNet)
REVENUES
Revenues	39,073	45,181	124,417	129,685
OPERATING EXPENSES
Total consolidated operating expenses	38,952	44,225	122,716	126,542
OPERATING INCOME
OPERATING INCOME	121	956	1,701	3,143
ASSETS
ASSETS	23,563		23,563		21,958
Operating Segments | Household Goods Moving Services (ABF Moving)
REVENUES
Revenues	31,040	43,076	74,926	93,870
OPERATING EXPENSES
Total consolidated operating expenses	29,054	40,048	72,819	89,207
OPERATING INCOME
OPERATING INCOME	1,986	3,028	2,107	4,663
ASSETS
ASSETS	26,988		26,988		28,547
Operating Segments | Asset-Light Logistics Segments
OPERATING EXPENSES
Pension settlement expense			100	100
Operating Segments | Asset-Light Logistics Segments | Maximum
OPERATING EXPENSES
Pension settlement expense	100	100
Other and eliminations
REVENUES
Revenues	(13,449)	(13,076)	(41,521)	(37,915)
OPERATING EXPENSES
Pension settlement expense	200	200	500	500
Total consolidated operating expenses	(9,279)	(11,428)	(32,146)	(30,439)
OPERATING INCOME
OPERATING INCOME	(4,170)	$ (1,648)	(9,375)	$ (7,476)
ASSETS
ASSETS	$ 178,194		$ 178,194		$ 227,247