GOODWILL AND OTHER INTANGIBLE ASSETS - Carrying Amount of Goodwill (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($)
Goodwill [Roll Forward]
Balance, beginning of period	$ 1,484,754
Foreign currency translation	3,862
Balance, end of period	1,488,616
NAST
Goodwill [Roll Forward]
Balance, beginning of period	1,196,333
Foreign currency translation	3,323
Balance, end of period	1,199,656
Global Forwarding
Goodwill [Roll Forward]
Balance, beginning of period	210,391
Foreign currency translation	634
Balance, end of period	211,025
All Other and Corporate
Goodwill [Roll Forward]
Balance, beginning of period	78,030
Foreign currency translation	(95)
Balance, end of period	$ 77,935