PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS (Details) (USD $)	3 Months Ended		9 Months Ended					1 Months Ended	3 Months Ended		9 Months Ended				3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Multiemployer pension plans ABF Freight plan	Sep. 30, 2014 Multiemployer pension plans Central States Pension Plan ABF Freight	Jan. 01, 2013 Multiemployer pension plans Central States Pension Plan ABF Freight	Jan. 31, 2014 Nonunion Defined Benefit Pension Plan person	Sep. 30, 2014 Nonunion Defined Benefit Pension Plan	Sep. 30, 2013 Nonunion Defined Benefit Pension Plan	Sep. 30, 2014 Nonunion Defined Benefit Pension Plan	Sep. 30, 2013 Nonunion Defined Benefit Pension Plan	Jan. 01, 2014 Nonunion Defined Benefit Pension Plan	Dec. 31, 2013 Nonunion Defined Benefit Pension Plan	Sep. 30, 2014 Supplemental Benefit Plan	Sep. 30, 2013 Supplemental Benefit Plan	Sep. 30, 2014 Supplemental Benefit Plan	Sep. 30, 2013 Supplemental Benefit Plan	Sep. 30, 2014 Postretirement Health Benefit Plan	Sep. 30, 2013 Postretirement Health Benefit Plan	Sep. 30, 2014 Postretirement Health Benefit Plan	Sep. 30, 2013 Postretirement Health Benefit Plan
Components of net periodic benefit cost
Service cost												$ 4,734,000							$ 70,000	$ 82,000	$ 210,000	$ 248,000
Interest cost									1,401,000	2,039,000	4,643,000	5,884,000			49,000	37,000	147,000	112,000	197,000	188,000	591,000	563,000
Expected return on plan assets									(2,544,000)	(3,438,000)	(7,980,000)	(9,747,000)
Amortization of prior service credit																			(47,000)	(47,000)	(142,000)	(142,000)
Pension settlement expense			5,405,000	1,834,000					805,000	1,834,000	5,405,000	1,834,000
Amortization of net actuarial loss									595,000	961,000	1,729,000	6,388,000			57,000	65,000	170,000	195,000	23,000	134,000	69,000	401,000
Net periodic benefit cost									257,000	1,396,000	3,797,000	9,093,000			106,000	102,000	317,000	307,000	243,000	357,000	728,000	1,070,000
Number of plan participants for which vested pension benefits were settled								375
Premium paid to purchase nonparticipating annuity contract								25,400,000
Pension benefit obligation settled with nonparticipating annuity contract								23,300,000
Lump-sum distributions									6,300,000		28,800,000
Pension settlement expense, net of tax	492,000	1,121,000	3,303,000	1,121,000					500,000		3,300,000
Unrecognized net actuarial loss									22,100,000		22,100,000
Amortization period for unrecognized net actuarial loss											8 years
Change in projected benefit obligation
Projected benefit obligation at the beginning of the period								211,660,000			211,660,000
Interest cost									1,401,000	2,039,000	4,643,000	5,884,000			49,000	37,000	147,000	112,000	197,000	188,000	591,000	563,000
Actuarial loss											10,413,000
Benefits paid											(54,593,000)
Projected benefit obligation at the end of the period									172,123,000		172,123,000
Change in plan assets
Fair value of plan assets at beginning of period								207,613,000			207,613,000
Actual return on plan assets											5,182,000
Benefits paid											(54,593,000)
Fair value of plan assets at end of period									158,202,000		158,202,000
Funded status									(13,921,000)		(13,921,000)
Accumulated benefit obligation									$ 172,123,000		$ 172,123,000
Discount rate (as a percent)									3.40%		3.40%			3.80%
Adjusted funding target attainment percentage													112.30%
Multiemployer Plans
Number of multiemployer plans to which ABF Freight currently contributes					25
Maximum required increase in employer's contribution to multiemployer plans that enter reorganization status (as a percent)					7.00%
Approximate proportion of multiemployer pension plan contributions made to Central States Pension Fund (as a percent)						50.00%
Actuarially certified funded percentage of multiemployer pension plan							47.60%