SEGMENT REPORTING - Reportable Segment Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($) employee	Mar. 31, 2021 USD ($) employee	Dec. 31, 2021 USD ($)
Segment Reporting Information [Line Items]
Total revenues	$ 6,815,953	$ 4,803,869
Income (loss) from operations	345,474	223,329
Depreciation and amortization	22,486	23,278
Total assets	$ 7,521,338	$ 5,596,623	$ 7,028,112
Average headcount (employee) | employee	17,258	14,997
NAST
Segment Reporting Information [Line Items]
Total revenues	$ 4,114,889	$ 3,211,423
Income (loss) from operations	182,354	136,784
Depreciation and amortization	6,239	6,625
Total assets	$ 3,701,164	$ 3,218,084
Average headcount (employee) | employee	7,348	6,537
Global Forwarding
Segment Reporting Information [Line Items]
Total revenues	$ 2,194,397	$ 1,156,039
Income (loss) from operations	167,638	90,589
Depreciation and amortization	5,555	5,649
Total assets	$ 2,940,486	$ 1,582,967
Average headcount (employee) | employee	5,610	4,735
All Other and Corporate
Segment Reporting Information [Line Items]
Total revenues	$ 506,667	$ 436,407
Income (loss) from operations	(4,518)	(4,044)
Depreciation and amortization	10,692	11,004
Total assets	$ 879,688	$ 795,572
Average headcount (employee) | employee	4,300	3,725