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LONG-TERM DEBT AND CURRENT PORTION OF LONG TERM DEBT (Details) |  |  |  |  | 3 Months Ended | 4 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | --- | --- | --- | ---
Oct. 16, 2020 USD ($) | Mar. 29, 2019 USD ($) | Feb. 12, 2019 USD ($) | Dec. 01, 2017 USD ($) Vessel | Dec. 31, 2019 USD ($) | Apr. 29, 2021 USD ($) | Dec. 31, 2020 USD ($) Lender Building Vessel | Dec. 16, 2020 USD ($)
Line of Credit Facility [Abstract] |  |  |  |  |  |  |  |
Number of lenders | Lender |  |  |  |  |  |  | 2 |
Current portion of long-term debt |  |  |  |  | $ 23,537,000 |  | $ 22,094,000 |
Number of new buildings | Building |  |  |  |  |  |  | 2 |
At-the-market offering of common Stock |  |  |  |  |  |  | $ 60,000,000 |
Contractual Obligation [Abstract] |  |  |  |  |  |  |  |
2021 |  |  |  |  |  |  | 24,765,000 |
2022 |  |  |  |  |  |  | 25,132,000 |
2023 |  |  |  |  |  |  | 25,516,000 |
2024 |  |  |  |  |  |  | 212,625,000 |
2025 |  |  |  |  |  |  | 9,535,000 |
More than 5 years |  |  |  |  |  |  | 68,567,000 |
Total |  |  |  |  |  |  | $ 366,140,000 |
Maximum [Member] |  |  |  |  |  |  |  |
Line of Credit Facility [Abstract] |  |  |  |  |  |  |  |
At-the-market offering of common Stock | $ 60,000,000 | $ 40,000,000 |  |  |  |  |  |
2019 Senior Secured Credit Facility [Member] |  |  |  |  |  |  |  |
Line of Credit Facility [Abstract] |  |  |  |  |  |  |  |
Number of vessels used as collateral | Vessel |  |  |  |  |  |  | 20 |
Debt instrument term |  |  |  |  |  |  | 5 years |
Maximum borrowing capacity |  |  | $ 306,100,000 |  |  |  |  |
Loan amortizing, maturity period |  |  |  |  |  |  | 20 years |
Maturity date |  |  |  |  |  |  | Feb. 28, 2024 |
Discretionary excess cash mechanism for the lender that equals to net earnings from collateral vessels |  |  | 50.00% |  |  |  |  |
Deferred financing costs |  |  | $ 13,000,000.0 |  | 2,600,000 |  | $ 2,400,000 |
Deferred finance costs, non-cash portion |  |  | 6,100,000 |  |  |  |  |
Debt covenants, minimum liquidity |  |  | $ 30,000,000.0 |  |  |  |  |
Debt covenants percentage in loan-to-vessel ratio |  |  | 70.00% |  |  |  |  |
Drawn amount |  |  |  |  | 291,800,000 |  | 253,900,000 |
Current portion of long-term debt |  |  |  |  | 16,100,000 |  | 14,400,000 |
Amount of excess cash flow payment related to earnings |  |  |  |  | 3,400,000 |  |  |
Repayment of debt |  |  |  |  |  |  | $ 67,900,000 |
2019 Senior Secured Credit Facility [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |
Line of Credit Facility [Abstract] |  |  |  |  |  |  |  |
Drawn amount |  |  |  |  |  | $ 249,700,000 |  |
Repayment of debt |  |  |  |  |  | $ 4,200,000 |  |
$30 Million Accordion Loan [Member] |  |  |  |  |  |  |  |
Line of Credit Facility [Abstract] |  |  |  |  |  |  |  |
Maximum borrowing capacity |  |  |  |  |  |  |  | $ 30,000,000.0
Maturity date |  |  |  |  |  |  | Feb. 28, 2024 |
Financing of 2018-built Vessels [Member] |  |  |  |  |  |  |  |
Line of Credit Facility [Abstract] |  |  |  |  |  |  |  |
Number of vessels delivered | Vessel |  |  |  | 3 |  |  |  |
Deferred financing costs |  |  |  | $ 2,300,000 |  |  |  |
Drawn amount |  |  |  |  | 119,900,000 |  | $ 112,200,000 |
Percentage of purchase price expected to pay by lending provider |  |  |  | 77.50% |  |  |  |
Term of bareboat charter agreement |  |  |  |  |  |  | 10 years |
Obligation to purchase the vessels |  |  |  | $ 13,600,000 |  |  |  |
First flexibility period to purchase the vessels |  |  |  |  |  |  | 60 months |
Second flexibility period to purchase the vessels |  |  |  |  |  |  | 84 months |
Minimum value adjusted equity |  |  |  | $ 175,000,000.0 |  |  |  |
Minimum value adjusted equity ratio |  |  |  | 25.00% |  |  |  |
Minimum liquidity value |  |  |  | $ 20,000,000.0 |  |  |  |
Long term debt current |  |  |  |  | $ 7,400,000 |  | $ 7,700,000 |
Number of new buildings | Building |  |  |  |  |  |  | 2 |
Maximum percentage of financing secured |  |  |  |  |  |  | 80.00% |
Debt |  |  |  |  |  |  | $ 0 |
Contractual Obligation [Abstract] |  |  |  |  |  |  |  |
2021 |  |  |  |  |  |  | 7,960,000 |
2022 |  |  |  |  |  |  | 8,327,000 |
2023 |  |  |  |  |  |  | 8,711,000 |
2024 |  |  |  |  |  |  | 9,138,000 |
2025 |  |  |  |  |  |  | 9,535,000 |
More than 5 years |  |  |  |  |  |  | 68,567,000 |
Total |  |  |  |  |  |  | 112,238,000 |
Financing of 2018-built Vessels [Member] | Minimum [Member] |  |  |  |  |  |  |  |
Line of Credit Facility [Abstract] |  |  |  |  |  |  |  |
Interest rate |  |  |  | 4.86% |  |  |  |
Financing of 2018-built Vessels [Member] | Maximum [Member] |  |  |  |  |  |  |  |
Line of Credit Facility [Abstract] |  |  |  |  |  |  |  |
Interest rate |  |  |  | 5.06% |  |  |  |
2019 Senior Secured Credit Facility including $30 mill Accordion Loan [Member] |  |  |  |  |  |  |  |
Contractual Obligation [Abstract] |  |  |  |  |  |  |  |
2021 |  |  |  |  |  |  | 16,805,000 |
2022 |  |  |  |  |  |  | 16,805,000 |
2023 |  |  |  |  |  |  | 16,805,000 |
2024 |  |  |  |  |  |  | 203,487,000 |
2025 |  |  |  |  |  |  | 0 |
More than 5 years |  |  |  |  |  |  | 0 |
Total |  |  |  |  |  |  | $ 253,902,000 |

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- Definition The carrying value as of the balance sheet date of the current portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(13)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(19)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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