EARNINGS PER SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	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
Basic earnings (loss) per share, numerator:
Net income (loss) attributable to Arkansas Best Corporation	$ (7,929)	$ 6,518	$ 11,841	$ (18,162)	$ 1,404	$ 12,265	$ 5,298	$ (12,808)	$ (7,732)		$ 6,159		$ (32,693)
Effect of unvested restricted stock awards									(149)		(249)		(69)
Adjusted net income (loss)									(7,881)		5,910		(32,762)
Basic earnings (loss) per share, denominator:
Weighted-average 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
Earnings (loss) per common share (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 earnings (loss) per share, numerator:
Net income (loss) attributable to Arkansas Best Corporation	(7,929)	6,518	11,841	(18,162)	1,404	12,265	5,298	(12,808)	(7,732)		6,159		(32,693)
Effect of unvested restricted stock awards									(149)		(249)		(69)
Adjusted net income (loss)									$ (7,881)		$ 5,910		$ (32,762)
Diluted earnings (loss) per share, denominator:
Weighted-average 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
Adjusted weighted-average shares and assumed conversions	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
Earnings (loss) per common share (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]
Outstanding stock awards not included in calculation of diluted earnings per share (in shares)									700,000		900,000		700,000

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