OPERATING SEGMENT DATA (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
REVENUES
Revenues	$ 648,134	$ 709,380	$ 696,115	$ 613,276	$ 664,848	$ 711,295	$ 658,646	$ 577,904	$ 2,666,905	$ 2,612,693	$ 2,299,549
OPERATING EXPENSES
Salaries, wages, and benefits									1,295,197	1,231,783	1,166,185
Rents, purchased transportation, and other costs of services									780,428	759,252	598,604
Fuel, supplies, and expenses									300,370	353,385	321,887
Depreciation and amortization									93,042	86,222	88,389
Gain on sale of property and equipment									(2,225)	(1,461)	(153)
Pension settlement expense									3,202	6,595	2,111
Other									122,372	112,812	105,414
Total consolidated operating expenses	640,822	675,942	662,649	611,996	646,799	678,354	631,694	586,606	2,591,409	2,543,454	2,280,479
OPERATING INCOME (LOSS)
OPERATING INCOME	7,312	33,438	33,466	1,280	18,049	32,941	26,952	(8,702)	75,496	69,239	19,070
OTHER INCOME (COSTS)
Interest and dividend income									1,284	851	681
Interest and other related financing costs									(4,400)	(3,190)	(4,183)
Other, net									354	3,712	3,893
TOTAL OTHER INCOME (COSTS)	$ (445)	$ (1,392)	$ (557)	$ (368)	$ 1,591	$ (385)	$ 419	$ (253)	(2,762)	1,373	391
INCOME BEFORE INCOME TAXES									72,734	70,612	19,461
Operating Segments | Freight Transportation (ABF Freight)
REVENUES
Revenues									1,918,450	1,930,990	1,761,716
OPERATING EXPENSES
Salaries, wages, and benefits									1,174,357	1,121,177	1,075,259
Fuel, supplies, and expenses									307,348	360,850	332,433
Operating taxes and licenses									48,992	46,955	43,865
Insurance									28,847	24,960	21,823
Communications and utilities									16,129	15,398	15,027
Depreciation and amortization									74,765	68,752	72,971
Rents and purchased transportation									197,073	229,443	180,689
Gain on sale of property and equipment									(1,734)	(1,471)	(576)
Pension settlement expense									2,404	5,309	1,831
Other									7,833	9,524	8,361
Total consolidated operating expenses									1,856,014	1,880,897	1,751,683
OPERATING INCOME (LOSS)
OPERATING INCOME									62,436	50,093	10,033
Operating Segments | Premium Logistics (Panther)
REVENUES
Revenues									300,368	316,668	246,849
OPERATING EXPENSES
Purchased transportation									220,994	235,006	188,561
Depreciation and amortization									11,436	11,362	10,516
Salaries, benefits, insurance, and other									57,140	54,660	40,816
Total consolidated operating expenses									289,570	301,028	239,893
OPERATING INCOME (LOSS)
OPERATING INCOME									10,798	15,640	6,956
Operating Segments | Transportation Management (ABF Logistics)
REVENUES
Revenues									203,529	152,632	105,223
OPERATING EXPENSES
Depreciation and amortization									1,138	1,006	640
Total consolidated operating expenses									197,668	148,797	102,250
OPERATING INCOME (LOSS)
OPERATING INCOME									5,861	3,835	2,973
Operating Segments | Emergency & Preventative Maintenance (FleetNet)
REVENUES
Revenues									174,952	158,581	137,546
OPERATING EXPENSES
Depreciation and amortization									1,119	961	540
Total consolidated operating expenses									171,998	155,459	134,272
OPERATING INCOME (LOSS)
OPERATING INCOME									2,954	3,122	3,274
Operating Segments | Household Goods Moving Services (ABF Moving)
REVENUES
Revenues									119,252	94,628	82,169
OPERATING EXPENSES
Depreciation and amortization									1,186	1,384	1,247
Total consolidated operating expenses									114,416	91,449	80,319
OPERATING INCOME (LOSS)
OPERATING INCOME									4,836	3,179	1,850
Operating Segments | Asset-Light Logistics Segments
OPERATING EXPENSES
Pension settlement expense									100	200
Other and eliminations
REVENUES
Revenues									(49,646)	(40,806)	(33,954)
OPERATING EXPENSES
Depreciation and amortization									3,398	2,757	2,475
Pension settlement expense									700	1,100	300
Total consolidated operating expenses									(38,257)	(34,176)	(27,938)
OPERATING INCOME (LOSS)
OPERATING INCOME									$ (11,389)	$ (6,630)	$ (6,016)