REVENUE FROM CONTRACTS WITH CUSTOMERS - Narrative (Details) - Product Concentration Risk - Revenue	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Transportation services
Disaggregation of Revenue [Line Items]
Percentage of revenues attributable to services	92.00%	91.00%
Sourcing
Disaggregation of Revenue [Line Items]
Percentage of revenues attributable to services	6.00%	7.00%
Value-added logistics services
Disaggregation of Revenue [Line Items]
Percentage of revenues attributable to services	2.00%	2.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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