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VESSELS (Details) $ in Thousands | 12 Months Ended
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Dec. 31, 2020 USD ($) Vessel Building | Dec. 31, 2019 USD ($) Vessel | Dec. 31, 2018 USD ($)
VESSELS [Abstract] |  |  |
Number of vessels | Vessel | 23 | 23 |
Vessels [Abstract] |  |  |
Total | $ 1,398,690 | $ 1,369,567 |
Less Accumulated Depreciation | (537,348) | (469,570) |
Less Accumulated Impairment Loss on Vessels | 0 | 0 |
Net Book Value Vessels | $ 861,342 | 899,997 |
Number of vessels the company taken through periodical maintenance survey | Vessel | 10 |  |
Vessels under construction | $ 11,000 | 0 |
Number of new buildings | Building | 2 |  |
Remaining commitments | $ 99,000 |  |
Percentage of remaining installments due in 2021 | 17.00% |  |
Percentage of remaining installments due in 2022 | 83.00% |  |
Impairment loss on vessels | $ 0 | 0 | $ 2,168
Vessels [Member] |  |  |
Vessels [Abstract] |  |  |
Additions | 6,845 | 2,531 |
Disposals | 0 | 0 |
Total | 1,309,618 | 1,307,087 |
Drydocking [Member] |  |  |
Vessels [Abstract] |  |  |
Additions | 22,278 | 7,618 |
Disposals | 0 | 0 |
Total | $ 59,949 | $ 52,331 |

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