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DESCRIPTION OF THE BUSINESS (Details)	6 Months Ended		9 Months Ended
	Jun. 30, 2021 segment	Jun. 30, 2020 segment	Sep. 30, 2021 segment facility
DESCRIPTION OF THE BUSINESS
Number of reportable segments | segment	2	2	2
Ocean Transportation | SSAT
DESCRIPTION OF THE BUSINESS
Ownership interest in SSAT (as a percent)			35.00%
Number of terminal facilities on which SSAT provided terminal and stevedoring services on the U.S. West Coast			7
MatNav | SSAT
DESCRIPTION OF THE BUSINESS
Number of terminal facilities on which SSAT provided terminal and stevedoring services on the U.S. West Coast			3

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Represents the number of ports terminal facilities on which the investee provides terminal and stevedoring services.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
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Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8672-108599

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