PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS (Details) (USD $)	3 Months Ended				1 Months Ended	3 Months Ended			3 Months Ended
	Mar. 31, 2013 ABF	Mar. 31, 2013 Multiemployer pension plans ABF plan	Mar. 31, 2013 Central States Pension Plan ABF	Jan. 02, 2012 Central States Pension Plan ABF	Apr. 30, 2013 Nonunion Defined Benefit Pension Plan	Mar. 31, 2013 Nonunion Defined Benefit Pension Plan	Mar. 31, 2012 Nonunion Defined Benefit Pension Plan	Jan. 02, 2013 Nonunion Defined Benefit Pension Plan	Mar. 31, 2013 Supplemental Benefit Pension Plan	Mar. 31, 2012 Supplemental Benefit Pension Plan	Mar. 31, 2013 Postretirement Health Benefit Plan	Mar. 31, 2012 Postretirement Health Benefit Plan
Components of net periodic benefit cost
Service cost						$ 2,367,000	$ 2,297,000				$ 83,000	$ 79,000
Interest cost						1,923,000	2,173,000		37,000	52,000	188,000	187,000
Expected return on plan assets						(3,154,000)	(3,016,000)
Amortization of prior service credit											(48,000)	(48,000)
Amortization of net actuarial loss and other						2,713,000	2,692,000		65,000	51,000	134,000	104,000
Net periodic benefit cost						3,849,000	4,146,000		102,000	103,000	357,000	322,000
Employer contribution					3,000,000
Estimated required minimum contribution in current fiscal year						$ 9,100,000
Adjusted funding target attainment percentage								92.00%
Multiemployer Plans
Number of multiemployer plans to which ABF 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				53.90%