REVENUE FROM CONTRACTS WITH CUSTOMERS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Total revenues	$ 4,224,800	$ 3,856,132	$ 11,657,654	$ 11,516,182
Operating Segments | NAST
Disaggregation of Revenue [Line Items]
Total revenues	2,923,842	2,826,308	8,222,879	8,495,145
Operating Segments | Global Forwarding
Disaggregation of Revenue [Line Items]
Total revenues	831,957	597,695	2,070,161	1,727,745
Operating Segments | All Other and Corporate
Disaggregation of Revenue [Line Items]
Total revenues	469,001	432,129	1,364,614	1,293,292
Transportation and logistics services
Disaggregation of Revenue [Line Items]
Total revenues	3,944,981	3,608,346	10,835,710	10,751,890
Transportation and logistics services | Performance obligations completed over time
Disaggregation of Revenue [Line Items]
Total revenues	3,944,981	3,608,346	10,835,710	10,751,890
Transportation and logistics services | Operating Segments | NAST | Performance obligations completed over time
Disaggregation of Revenue [Line Items]
Total revenues	2,923,842	2,826,308	8,222,879	8,495,145
Transportation and logistics services | Operating Segments | Global Forwarding | Performance obligations completed over time
Disaggregation of Revenue [Line Items]
Total revenues	831,957	597,695	2,070,161	1,727,745
Transportation and logistics services | Operating Segments | All Other and Corporate | Performance obligations completed over time
Disaggregation of Revenue [Line Items]
Total revenues	189,182	184,343	542,670	529,000
Sourcing
Disaggregation of Revenue [Line Items]
Total revenues	279,819	247,786	821,944	764,292
Sourcing | Performance obligations completed at a point in time
Disaggregation of Revenue [Line Items]
Total revenues	279,819	247,786	821,944	764,292
Sourcing | Operating Segments | NAST | Performance obligations completed at a point in time
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Sourcing | Operating Segments | Global Forwarding | Performance obligations completed at a point in time
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Sourcing | Operating Segments | All Other and Corporate | Performance obligations completed at a point in time
Disaggregation of Revenue [Line Items]
Total revenues	$ 279,819	$ 247,786	$ 821,944	$ 764,292