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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Concentration Risk (Details) $ in Thousands | 12 Months Ended
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Dec. 31, 2017 USD ($) customer item | Dec. 31, 2016 customer item | Dec. 31, 2015 customer
Concentration Risk |  |  |
Number of financial institutions with which the entity maintains its cash and cash equivalents | item | 3 | 4 |
Cash insured by financial institutions | $ | $ 0 |  |
Voyage Revenues | Customer Concentration Risk |  |  |
Concentration Risk |  |  |
Percentage of revenue earned (as a percent) | 100.00% |  |
Number of customers | 102 | 52 | 52
Major Customers | 2 | 3 | 3
Concentration risk percentage (as a percent) | 10.00% | 10.00% | 10.00%
Voyage Revenues | Customer Concentration Risk | Swissmarine Services S.A. |  |  |
Concentration Risk |  |  |
Concentration risk percentage (as a percent) | 15.09% | 25.31% | 24.37%
Voyage Revenues | Customer Concentration Risk | Clipper Group |  |  |
Concentration Risk |  |  |
Concentration risk percentage (as a percent) | 10.98% | 22.96% | 19.09%
Voyage Revenues | Customer Concentration Risk | Pioneer Navigation Ltd |  |  |
Concentration Risk |  |  |
Concentration risk percentage (as a percent) |  | 11.11% | 13.03%

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- Definition Represents the number customers of the entity from which revenue was earned. + References No definition available. + Details
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- Definition Represents the number of financial institutions with which the entity maintains its cash and cash equivalents. + References No definition available. + Details
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- Definition Percentage of revenue earned from customers. + References No definition available. + Details
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- Definition Represents the number of external customers from which the entity generated 10 percent or more of revenues. + References No definition available. + Details
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- Definition The amount of cash deposited in financial institutions as of the balance sheet date that is insured by the Federal Deposit Insurance Corporation. + References No definition available. + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition 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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=64851502&loc=d3e6351-108592 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13531-108611 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=64851502&loc=d3e6404-108592 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13537-108611 + Details
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- Details
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