EARNINGS PER SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Basic loss per share, numerator:
Net loss attributable to Arkansas Best Corporation	$ (18,162)	$ (12,808)
Effect of unvested restricted stock awards	(34)	(30)
Adjusted net loss	(18,196)	(12,838)
Basic loss per share, denominator:
Weighted-average shares (in shares)	25,455,607	25,296,854
Loss per common share (in dollars per share)	$ (0.71)	$ (0.51)
Diluted loss per share, numerator:
Net loss attributable to Arkansas Best Corporation	(18,162)	(12,808)
Effect of unvested restricted stock awards	(34)	(30)
Adjusted net loss	$ (18,196)	$ (12,838)
Diluted loss per share, denominator:
Weighted-average shares (in shares)	25,455,607	25,296,854
Adjusted weighted-average shares and assumed conversions (in shares)	25,455,607	25,296,854
Loss per common share (in dollars per share)	$ (0.71)	$ (0.51)
Outstanding stock awards not included in calculation of diluted loss per share (in shares)	800,000	800,000