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Significant Accounting Policies - 20F (Details) $ / shares in Units, $ in Thousands | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Dec. 31, 2015 USD ($) | Sep. 30, 2015 | Dec. 31, 2015 USD ($) Segment $ / shares | Dec. 31, 2014 USD ($) | Dec. 31, 2013 USD ($)
Accounts Receivable Trade, Net [Abstract] |  |  |  |  |
Provision for doubtful accounts | $ 43 |  | $ 43 | $ 13 |
Impairment of Long-Lived Assets (Vessels) [Abstract] |  |  |  |  |
Period of forward freight agreements |  |  | 2 years |  |
Period within which historical charter rates available for each type of vessel |  |  | 10 years |  |
Annual inflation rate assumed for asset impairment |  |  | 2.00% |  |
Impairment loss for vessels |  |  | $ 0 | 0 | $ 3,564
Income Taxes [Abstract] |  |  |  |  |
Minimum percentage for recognition of income tax position |  |  | 50.00% |  |
Hong Kong tax rate |  |  | 16.50% |  |
Foreign exchange tax |  |  | $ 32 |  |
Minimum stock ownership percentage for tax exemption | 50.00% |  | 50.00% |  |
Minimum vote and value percentage of regularly traded stock | 50.00% |  | 50.00% |  |
Significant shareholder percentage | 5.00% |  | 5.00% |  |
Minimum percentages of shipping income would be treated as being United States source income |  |  | 50.00% |  |
Tax rate on US source shipping income | 2.00% |  | 2.00% |  |
Unrecognized tax expense for tax exempt entity |  |  | $ 0 | $ 0 | 25
Segment Reporting [Abstract] |  |  |  |  |
Number of reportable segments | Segment |  |  | 1 |  |
Salvage Value Change [Member] |  |  |  |  |
Asset Depreciation, Salvage Value and Estimated Useful Life [Abstract] |  |  |  |  |
Increase in depreciation expense |  |  | $ 235 |  |
Increase in depreciation expense (in dollars per share) | $ / shares |  |  | $ 0.02 |  |
Estimated Useful Life Change [Member] |  |  |  |  |
Asset Depreciation, Salvage Value and Estimated Useful Life [Abstract] |  |  |  |  |
Increase in depreciation expense |  |  | $ 289 |  |
Increase in depreciation expense (in dollars per share) | $ / shares |  |  | $ 0.03 |  |
Computer Software and Hardware [Member] |  |  |  |  |
Asset Depreciation, Salvage Value and Estimated Useful Life [Abstract] |  |  |  |  |
Estimated useful life of property and equipment |  |  | 3 years |  |
Vessel [Member] |  |  |  |  |
Asset Depreciation, Salvage Value and Estimated Useful Life [Abstract] |  |  |  |  |
Estimated useful life of property and equipment | 25 years | 30 years |  |  |
African Oryx [Member] |  |  |  |  |
Vessels Held for Sale [Abstract] |  |  |  |  |
Impairment loss |  |  |  |  | 867
Vessels Davakis G. and Delos Ranger [Member] |  |  |  |  |
Vessels Held for Sale [Abstract] |  |  |  |  |
Impairment loss |  |  |  |  | 10,697
Vessels remeasurement |  |  |  |  | 7,000
UOB Vessels [Member] |  |  |  |  |
Vessels Held for Sale [Abstract] |  |  |  |  |
Vessels remeasurement |  |  |  |  | $ 1,000
Minimum [Member] |  |  |  |  |
Dry-Docking and Special Survey Costs [Abstract] |  |  |  |  |
Dry-docking and special survey cost amortization period |  |  | 2 years |  |
Maximum [Member] |  |  |  |  |
Dry-Docking and Special Survey Costs [Abstract] |  |  |  |  |
Dry-docking and special survey cost amortization period |  |  | 3 years |  |

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