REVENUE FROM CONTRACTS WITH CUSTOMERS - Total Revenues Disaggregated by Major Service Line and Timing of Recognition (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Total revenues	$ 4,137,908	$ 4,291,900	$ 4,276,037	$ 3,925,327	$ 3,959,786	$ 3,784,451	$ 3,710,018	$ 3,415,125	$ 16,631,172	$ 14,869,380	$ 13,144,413
Operating Segments | NAST
Disaggregation of Revenue [Line Items]
Total revenues									11,247,900	9,728,810	8,737,716
Operating Segments | Global Forwarding
Disaggregation of Revenue [Line Items]
Total revenues									2,487,744	2,140,987	1,574,686
Operating Segments | Robinson Fresh
Disaggregation of Revenue [Line Items]
Total revenues									2,268,900	2,415,740	2,344,131
Operating Segments | All Other and Corporate
Disaggregation of Revenue [Line Items]
Total revenues									626,628	583,843	487,880
Transportation and logistics services
Disaggregation of Revenue [Line Items]
Total revenues	3,896,750	4,028,392	3,953,139	3,637,640	3,647,167	3,433,701	3,319,995	3,102,043	15,515,921	13,502,906	11,704,745
Transportation and logistics services | Performance obligations completed over time
Disaggregation of Revenue [Line Items]
Total revenues									15,515,921
Transportation and logistics services | Operating Segments | NAST
Disaggregation of Revenue [Line Items]
Total revenues									11,247,900
Transportation and logistics services | Operating Segments | NAST | Performance obligations completed over time
Disaggregation of Revenue [Line Items]
Total revenues									11,247,900
Transportation and logistics services | Operating Segments | Global Forwarding
Disaggregation of Revenue [Line Items]
Total revenues									2,487,744
Transportation and logistics services | Operating Segments | Global Forwarding | Performance obligations completed over time
Disaggregation of Revenue [Line Items]
Total revenues									2,487,744
Transportation and logistics services | Operating Segments | Robinson Fresh
Disaggregation of Revenue [Line Items]
Total revenues									1,153,649
Transportation and logistics services | Operating Segments | Robinson Fresh | Performance obligations completed over time
Disaggregation of Revenue [Line Items]
Total revenues									1,153,649
Transportation and logistics services | Operating Segments | All Other and Corporate
Disaggregation of Revenue [Line Items]
Total revenues									626,628
Transportation and logistics services | Operating Segments | All Other and Corporate | Performance obligations completed over time
Disaggregation of Revenue [Line Items]
Total revenues									626,628
Sourcing
Disaggregation of Revenue [Line Items]
Total revenues	$ 241,158	$ 263,508	$ 322,898	$ 287,687	$ 312,619	$ 350,750	$ 390,023	$ 313,082	1,115,251	$ 1,366,474	$ 1,439,668
Sourcing | Performance obligations completed at a point in time
Disaggregation of Revenue [Line Items]
Total revenues									1,115,251
Sourcing | Operating Segments | NAST
Disaggregation of Revenue [Line Items]
Total revenues									0
Sourcing | Operating Segments | NAST | Performance obligations completed at a point in time
Disaggregation of Revenue [Line Items]
Total revenues									0
Sourcing | Operating Segments | Global Forwarding
Disaggregation of Revenue [Line Items]
Total revenues									0
Sourcing | Operating Segments | Global Forwarding | Performance obligations completed at a point in time
Disaggregation of Revenue [Line Items]
Total revenues									0
Sourcing | Operating Segments | Robinson Fresh
Disaggregation of Revenue [Line Items]
Total revenues									1,115,251
Sourcing | Operating Segments | Robinson Fresh | Performance obligations completed at a point in time
Disaggregation of Revenue [Line Items]
Total revenues									1,115,251
Sourcing | Operating Segments | All Other and Corporate
Disaggregation of Revenue [Line Items]
Total revenues									0
Sourcing | Operating Segments | All Other and Corporate | Performance obligations completed at a point in time
Disaggregation of Revenue [Line Items]
Total revenues									$ 0