GOODWILL AND OTHER INTANGIBLE ASSETS - Change in the Carrying Amount of Goodwill (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017 USD ($)
Goodwill [Roll Forward]
Balance, beginning of period	$ 1,232,796
Acquisitions	28,575
Translation	14,179
Balance, end of period	1,275,550
NAST
Goodwill [Roll Forward]
Balance, beginning of period	907,230
Acquisitions	3,673
Translation	10,320
Balance, end of period	921,223
Global Forwarding
Goodwill [Roll Forward]
Balance, beginning of period	159,050
Acquisitions	24,902
Translation	1,970
Balance, end of period	185,922
Robinson Fresh
Goodwill [Roll Forward]
Balance, beginning of period	139,558
Acquisitions	0
Translation	1,583
Balance, end of period	141,141
All Other and Corporate
Goodwill [Roll Forward]
Balance, beginning of period	26,958
Acquisitions	0
Translation	306
Balance, end of period	$ 27,264