QUARTERLY RESULTS OF OPERATIONS (UNAUDITED) (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
QUARTERLY RESULTS OF OPERATIONS (UNAUDITED)
Operating revenues	$ 537,042,000	$ 577,546,000	$ 510,543,000	$ 440,867,000	$ 463,241,000	$ 510,887,000	$ 498,550,000	$ 434,931,000	$ 2,065,999,000		$ 1,907,609,000		$ 1,657,864,000
Operating expenses and costs	548,058,000	565,313,000	503,342,000	463,854,000	461,606,000	489,769,000	489,552,000	456,923,000	2,080,567,000		1,897,850,000		1,712,409,000
Operating income (loss)	(11,016,000)	12,233,000	7,201,000	(22,987,000)	1,635,000	21,118,000	8,998,000	(21,992,000)	(14,568,000)		9,759,000		(54,545,000)
Other income (expense), net	(1,300,000)	(457,000)	(1,117,000)	451,000	299,000	(2,045,000)	(378,000)	1,859,000	(2,424,000)		(266,000)		748,000
Income tax provision (benefit)	(4,387,000)	5,258,000	(5,757,000)	(4,374,000)	530,000	6,808,000	3,169,000	(7,346,000)	(9,260,000)		3,160,000		(21,376,000)
NET INCOME (LOSS)					1,404,000	12,265,000	5,451,000	(12,787,000)	(7,732,000)		6,333,000		(32,421,000)
LESS: NONCONTROLLING INTEREST IN NET INCOME OF SUBSIDIARY							153,000	21,000			174,000		272,000
Net income (loss) attributable to Arkansas Best Corporation	(7,929,000)	6,518,000	11,841,000	(18,162,000)	1,404,000	12,265,000	5,298,000	(12,808,000)	(7,732,000)		6,159,000		(32,693,000)
Earnings (loss) per common share
Basic (in dollars per share)	$ (0.31)	$ 0.24	$ 0.44	$ (0.71)	$ 0.05	$ 0.46	$ 0.20	$ (0.51)	$ (0.31)	[1]	$ 0.23	[1]	$ (1.30)	[1]
Diluted (in dollars per share)	$ (0.31)	$ 0.24	$ 0.44	$ (0.71)	$ 0.05	$ 0.46	$ 0.20	$ (0.51)	$ (0.31)	[1]	$ 0.23	[1]	$ (1.30)	[1]
Average common shares outstanding
Basic (in shares)	25,629,309	25,613,315	25,544,455	25,455,607	25,421,887	25,421,887	25,411,339	25,296,854	25,564,752		25,403,073		25,187,723
Diluted (in shares)	25,629,309	25,613,315	25,544,455	25,455,607	25,421,887	25,421,887	25,411,942	25,296,854	25,564,752		25,403,073		25,187,723
After-tax adjustment to correct the reserves for workers' compensation and third-party casualty claims	$ 2,700,000

[1] The Company uses the two-class method for calculating earnings per share. See Note M.