EARNINGS PER SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Basic earnings (loss) per share, numerator:
Net income (loss) attributable to Arkansas Best Corporation	$ 11,841	$ 5,298	$ (6,321)	$ (7,510)
Effect of unvested restricted stock awards	(549)	(213)	(75)	(60)
Adjusted net income (loss)	11,292	5,085	(6,396)	(7,570)
Basic earnings (loss) per share, denominator:
Weighted-average shares	25,544,455	25,411,339	25,496,871	25,358,130
Earnings (loss) per common share (in dollars per share)	$ 0.44	$ 0.20	$ (0.25)	$ (0.30)
Diluted earnings (loss) per share, numerator:
Net income (loss) attributable to Arkansas Best Corporation	11,841	5,298	(6,321)	(7,510)
Effect of unvested restricted stock awards	(549)	(213)	(75)	(60)
Adjusted net income (loss)	$ 11,292	$ 5,085	$ (6,396)	$ (7,570)
Diluted earnings (loss) per share, denominator:
Weighted-average shares	25,544,455	25,411,339	25,496,871	25,358,130
Effect of dilutive securities (in shares)		603
Adjusted weighted-average shares and assumed conversions	25,544,455	25,411,942	25,496,871	25,358,130
Earnings (loss) per common share (in dollars per share)	$ 0.44	$ 0.20	$ (0.25)	$ (0.30)
Outstanding stock awards not included in calculation of diluted loss per share (in shares)	900,000	900,000	800,000	900,000