GOODWILL AND INTANGIBLE ASSETS (Goodwill) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 01, 2015	Jan. 02, 2015	Apr. 30, 2014
Goodwill by reportable operating segment
Balance at the beginning of the period	$ 77,078	$ 76,448
Goodwill acquired	19,387	630
Balance at the end of the period	96,465	77,078
Impairment of goodwill balances	0	0
Premium Logistics (Panther)
Goodwill by reportable operating segment
Balance at the beginning of the period	71,096	71,096
Balance at the end of the period	71,096	71,096
Household Goods Moving Services (ABF Moving)
Goodwill by reportable operating segment
Balance at the beginning of the period	5,352	5,352
Balance at the end of the period	5,352	5,352
Transportation Management (ABF Logistics)
Goodwill by reportable operating segment
Goodwill acquired	19,387
Balance at the end of the period	19,387
Emergency & Preventative Maintenance (FleetNet)
Goodwill by reportable operating segment
Balance at the beginning of the period	630
Goodwill acquired		630
Balance at the end of the period	$ 630	$ 630
Goodwill related to acquisition expected to be fully tax deductible					$ 600
Smart Lines Transportation Group, LLC | Transportation Management (ABF Logistics)
Goodwill by reportable operating segment
Goodwill related to acquisition expected to be fully tax deductible				$ 4,200
Bear Transportation Services, L.P. | Transportation Management (ABF Logistics)
Goodwill by reportable operating segment
Goodwill related to acquisition expected to be fully tax deductible			$ 15,200