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LONG-TERM DEBT AND CURRENT PORTION OF LONG-TERM DEBT (Details) $ in Thousands |  |  |  | 12 Months Ended |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Apr. 29, 2025 Vessel | Feb. 06, 2025 USD ($) Vessel | Dec. 01, 2017 USD ($) | Dec. 31, 2024 USD ($) Lender Vessel | Dec. 31, 2022 USD ($) Vessel Building | Dec. 31, 2020 USD ($) Building | Dec. 31, 2018 Building Vessel | Dec. 31, 2016 Building | Aug. 31, 2025 USD ($) | Jul. 31, 2025 USD ($) | Dec. 31, 2023 USD ($) | Dec. 31, 2021 USD ($) | Dec. 16, 2020 USD ($) | Feb. 12, 2019 USD ($)
Line of Credit Facility [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of lenders | Lender |  |  |  | 2 |  |  |  |  |  |  |  |  |  |
Number of vessels used as collateral | Vessel |  |  |  | 20 |  |  |  |  |  |  |  |  |  |
Current portion of long-term debt |  |  |  | $ 21,560 |  |  |  |  |  |  | $ 31,898 |  |  |
Number of new buildings | Building |  |  |  |  | 2 |  | 1 | 1 |  |  |  |  |  |
Contractual Obligation [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |
2025 |  |  |  | 93,595 |  |  |  |  |  |  |  |  |  |
2026 |  |  |  | 21,474 |  |  |  |  |  |  |  |  |  |
2027 |  |  |  | 21,643 |  |  |  |  |  |  |  |  |  |
2028 |  |  |  | 59,981 |  |  |  |  |  |  |  |  |  |
2029 |  |  |  | 11,500 |  |  |  |  |  |  |  |  |  |
More than 5 years |  |  |  | 63,829 |  |  |  |  |  |  |  |  |  |
Total |  |  |  | 272,022 |  |  |  |  |  |  |  |  |  |
Cash balance |  |  |  | $ 44,384 | $ 63,302 |  |  |  |  |  | 33,361 | $ 44,648 |  |
2019 Senior Secured Credit Facility [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of vessels used as collateral | Vessel |  |  |  | 14 |  |  |  |  |  |  |  |  |  |
Debt instrument term |  |  |  | 5 years |  |  |  |  |  |  |  |  |  |
Maximum borrowing capacity |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 306,100
Loan amortizing, maturity period |  |  |  | 20 years |  |  |  |  |  |  |  |  |  |
Maturity date |  |  |  | Feb. 28, 2025 |  |  |  |  |  |  |  |  |  |
Deferred financing costs |  |  |  | $ 70 |  |  |  |  |  |  |  |  |  |
Drawn amount |  |  |  | 72,600 |  |  |  |  |  |  |  |  |  |
Current portion of long-term debt |  |  |  | $ 1,000 |  |  |  |  |  |  |  |  |  |
$30 Million Accordion Loan [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Maximum borrowing capacity |  |  |  |  |  |  |  |  |  |  |  |  | $ 30,000 |
Maturity date |  |  |  | Feb. 28, 2025 |  |  |  |  |  |  |  |  |  |
Financing of 2018-built Vessels [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of vessels delivered | Vessel |  |  |  |  |  |  | 3 |  |  |  |  |  |  |
Deferred financing costs |  |  | $ 2,300 |  |  |  |  |  |  |  |  |  |  |
Drawn amount |  |  |  | $ 78,100 |  |  |  |  |  |  | 87,200 |  |  |
Percentage of purchase price expected to pay by lending provider |  |  | 77.50% |  |  |  |  |  |  |  |  |  |  |
Term of bareboat charter agreement |  |  |  | 10 years |  |  |  |  |  |  |  |  |  |
Obligation to purchase vessels |  |  | $ 13,600 |  |  |  |  |  |  |  |  |  |  |
Second flexibility period to purchase the vessels |  |  |  | 84 months |  |  |  |  |  |  |  |  |  |
Basis spread on margin |  |  |  | 4.52% |  |  |  |  |  |  |  |  |  |
Basis spread on variable rate |  |  |  | 0.26% |  |  |  |  |  |  |  |  |  |
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration] |  |  |  | us-gaap:SecuredOvernightFinancingRateSofrMember |  |  |  |  |  |  |  |  |  |
Minimum value adjusted equity |  |  | $ 175,000 |  |  |  |  |  |  |  |  |  |  |
Minimum value adjusted equity ratio |  |  | 25.00% |  |  |  |  |  |  |  |  |  |  |
Minimum liquidity value |  |  | $ 20,000 |  |  |  |  |  |  |  |  |  |  |
Long term debt current |  |  |  | $ 9,300 |  |  |  |  |  |  | 8,900 |  |  |
Contractual Obligation [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |
2025 |  |  |  | 9,534 |  |  |  |  |  |  |  |  |  |
2026 |  |  |  | 9,974 |  |  |  |  |  |  |  |  |  |
2027 |  |  |  | 10,143 |  |  |  |  |  |  |  |  |  |
2028 |  |  |  | 48,450 |  |  |  |  |  |  |  |  |  |
2029 |  |  |  | 0 |  |  |  |  |  |  |  |  |  |
More than 5 years |  |  |  | 0 |  |  |  |  |  |  |  |  |  |
Total |  |  |  | 78,101 |  |  |  |  |  |  |  |  |  |
Financing of 2018-built Vessels [Member] | Forecast [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of vessels declared to purchase | Vessel | 2 |  |  |  |  |  |  |  |  |  |  |  |  |
Contractual Obligation [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total |  |  |  |  |  |  |  |  | $ 24,000 | $ 24,000 |  |  |  |
2019 Senior Secured Credit Facility including $30 mill Accordion Loan [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Contractual Obligation [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |
2025 |  |  |  | 72,561 |  |  |  |  |  |  |  |  |  |
2026 |  |  |  | 0 |  |  |  |  |  |  |  |  |  |
2027 |  |  |  | 0 |  |  |  |  |  |  |  |  |  |
2028 |  |  |  | 0 |  |  |  |  |  |  |  |  |  |
2029 |  |  |  | 0 |  |  |  |  |  |  |  |  |  |
More than 5 years |  |  |  | 0 |  |  |  |  |  |  |  |  |  |
Total |  |  |  | $ 72,561 |  |  |  |  |  |  |  |  |  |
Amended and Restated Agreement [Member] | Beal Bank [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument term |  |  |  | 5 years |  |  |  |  |  |  |  |  |  |
Amended and Restated Agreement [Member] | Beal Bank [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of vessels used as collateral | Vessel |  | 7 |  |  |  |  |  |  |  |  |  |  |  |
Maximum borrowing capacity |  | $ 150,000 |  |  |  |  |  |  |  |  |  |  |  |
Amended and Restated Agreement [Member] | LTV Ratio Less than 50% [Member] | Beal Bank [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Excess cash sweep percentage |  | 25.00% |  |  |  |  |  |  |  |  |  |  |  |
Amended and Restated Agreement [Member] | LTV Ratio, Greater than or Equal to 50% but Less than 70% [Member] | Beal Bank [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Excess cash sweep percentage |  | 50.00% |  |  |  |  |  |  |  |  |  |  |  |
Amended and Restated Agreement [Member] | LTV Ratio, More than or Equal to 70% [Member] | Beal Bank [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Excess cash sweep percentage |  | 100.00% |  |  |  |  |  |  |  |  |  |  |  |
Financing of 2022-built Vessels [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of vessels delivered | Vessel |  |  |  |  | 2 |  |  |  |  |  |  |  |  |
Deferred financing costs |  |  |  | $ 5,400 |  |  |  |  |  |  | 5,400 |  |  |
Drawn amount |  |  |  | $ 73,800 |  |  |  |  |  |  | 79,400 |  |  |
Percentage of purchase price expected to pay by lending provider |  |  |  |  | 80.00% |  |  |  |  |  |  |  |  |
Term of bareboat charter agreement |  |  |  | 10 years |  |  |  |  |  |  |  |  |  |
Obligation to purchase vessels |  |  |  |  |  | $ 16,500 |  |  |  |  |  |  |  |
First flexibility period to purchase the vessels |  |  |  | 60 months |  |  |  |  |  |  |  |  |  |
Second flexibility period to purchase the vessels |  |  |  | 84 months |  |  |  |  |  |  |  |  |  |
Basis spread on margin |  |  |  | 4.50% |  |  |  |  |  |  |  |  |  |
Basis spread on variable rate |  |  |  | 0.26% |  |  |  |  |  |  |  |  |  |
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration] |  |  |  | us-gaap:SecuredOvernightFinancingRateSofrMember |  |  |  |  |  |  |  |  |  |
Minimum liquidity value |  |  |  | $ 20,000 |  |  |  |  |  |  |  |  |  |
Number of new buildings | Building |  |  |  |  |  | 2 |  |  |  |  |  |  |  |
Contractual Obligation [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |
2025 |  |  |  | 5,500 |  |  |  |  |  |  |  |  |  |
2026 |  |  |  | 5,500 |  |  |  |  |  |  |  |  |  |
2027 |  |  |  | 5,500 |  |  |  |  |  |  |  |  |  |
2028 |  |  |  | 5,515 |  |  |  |  |  |  |  |  |  |
2029 |  |  |  | 5,500 |  |  |  |  |  |  |  |  |  |
More than 5 years |  |  |  | 46,321 |  |  |  |  |  |  |  |  |  |
Total |  |  |  | 73,836 |  |  |  |  |  |  |  |  |  |
Financing of Nordic Hawk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Drawn amount |  |  |  | $ 47,500 |  |  |  |  |  |  | 53,500 |  |  |
Percentage of purchase price expected to pay by lending provider |  |  |  | 75.00% |  |  |  |  |  |  |  |  |  |
Term of bareboat charter agreement |  |  |  | 8 years |  |  |  |  |  |  |  |  |  |
Obligation to purchase vessels |  |  |  | $ 5,900 |  |  |  |  |  |  |  |  |  |
First flexibility period to purchase the vessels |  |  |  | 60 months |  |  |  |  |  |  |  |  |  |
Second flexibility period to purchase the vessels |  |  |  | 84 months |  |  |  |  |  |  |  |  |  |
Basis spread on variable rate |  |  |  | 4.76% |  |  |  |  |  |  |  |  |  |
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration] |  |  |  | nat:TermSecuredOvernightFinancingRateSOFRMember |  |  |  |  |  |  |  |  |  |
Minimum liquidity value |  |  |  | $ 20,000 |  |  |  |  |  |  |  |  |  |
Long term debt current |  |  |  | 5,900 |  |  |  |  |  |  | $ 5,900 |  |  |
Contractual Obligation [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |
2025 |  |  |  | 6,000 |  |  |  |  |  |  |  |  |  |
2026 |  |  |  | 6,000 |  |  |  |  |  |  |  |  |  |
2027 |  |  |  | 6,000 |  |  |  |  |  |  |  |  |  |
2028 |  |  |  | 6,016 |  |  |  |  |  |  |  |  |  |
2029 |  |  |  | 6,000 |  |  |  |  |  |  |  |  |  |
More than 5 years |  |  |  | 17,508 |  |  |  |  |  |  |  |  |  |
Total |  |  |  | $ 47,524 |  |  |  |  |  |  |  |  |  |

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- Definition Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 45 -Paragraph 1A -Publisher FASB -URI https://asc.fasb.org/1943274/2147482925/835-30-45-1A Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482925/835-30-45-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482900/835-30-50-1 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1D -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1D + Details
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- Definition The carrying value as of the balance sheet date of the current and noncurrent portions 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 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -SubTopic 10 -Topic 210 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)(a)(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 + Details
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- Definition Date the credit facility terminates, in YYYY-MM-DD format. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(19)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 + Details
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- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(19)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 + Details
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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 -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(19)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(13)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 + Details
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- Definition Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt classified as current. Excludes lease obligation. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(20)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 + Details
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