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INVESTMENTS (Details) |  |  |  |  | 1 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | --- | --- | --- | --- | ---
Mar. 28, 2017 USD ($) $ / shares shares | Feb. 28, 2016 shares | Jun. 30, 2014 USD ($) shares | Nov. 18, 2013 USD ($) shares | Nov. 30, 2015 shares | Nov. 30, 2013 shares | Apr. 30, 2013 shares | Dec. 31, 2016 USD ($) $ / shares shares | Dec. 31, 2015 USD ($) shares | Dec. 31, 2014 USD ($) shares | May 30, 2015 shares | Dec. 31, 2007 $ / shares
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Private equity placement issued amount |  |  |  |  |  |  |  | $ 120,069,000 |  | $ 113,433,000 |  |
Shares as dividend-in-kind (in shares) | shares |  |  |  |  |  |  |  |  |  | 699,802 |  |
Gain on investment |  |  |  |  |  |  |  | $ (46,642,000) | $ (2,462,000) | $ 1,559,000 |  |
Company acquired additional shares in open market (in shares) | shares |  |  |  |  |  |  |  |  |  | 488,216 |  |
Carrying value per share (in dollars per share) | $ / shares |  |  |  |  |  |  |  | 8.95 |  |  |  |
Impairment of investment |  |  |  |  |  |  |  | $ 37,324,000 |  |  |  |
NATs share of NAOs total market capitalization |  |  |  |  |  |  |  |  | 31,700,000 |  |  |
Common shares issued in public offering (in shares) | shares |  |  |  |  |  | 9,343,750 | 11,212,500 |  |  |  |  |
Public offering Price (in dollars per share) | $ / shares |  |  |  |  |  |  |  | $ 2.75 |  |  |  | $ 115
Summarized Statement of Operations information [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
NATs portion of NAOs Net (Loss) Income |  |  |  |  |  |  |  | $ 0 | $ 0 | $ 1,929,000 |  |
Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Common shares issued in public offering (in shares) | shares | 8,000,000 |  |  |  |  |  |  |  |  |  |  |
Public offering Price (in dollars per share) | $ / shares | $ 1.25 |  |  |  |  |  |  |  |  |  |  |
Common shares issued in public offering including exercise of underwriters' option (in shares) | shares | 1,300,000 |  |  |  |  |  |  |  |  |  |  |
Nordic American Offshore Repurchase Program [Member] |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Repurchase Program, shares authorized to be repurchased (in shares) | shares |  |  |  |  |  |  |  |  |  |  | 2,500,000 |
Shares repurchased during the period (in shares) | shares |  |  |  |  |  |  |  | 1,172,774 | 870,839 |  |  |
Remaining shares available to be repurchased (in shares) | shares |  |  |  |  |  |  |  | 20,686,847 | 22,560,531 |  |  |
Nordic American Offshore Limited [Member] |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Gain on investment |  |  |  |  |  |  |  |  |  | $ 2,100,000 |  |
Company acquired additional shares in private transaction (in shares) | shares |  |  |  |  | 1,521,300 |  |  |  |  |  |  |
Ownership interest |  |  |  |  | 26.50% |  |  | 29.10% | 26.70% | 19.20% |  |
Financial Position [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Current assets |  |  |  |  |  |  |  | $ 7,909,000 | $ 14,565,000 |  |  |
Noncurrent assets |  |  |  |  |  |  |  | 366,945,000 | 321,635,000 |  |  |
Total Assets |  |  |  |  |  |  |  | 374,854,000 | 336,200,000 |  |  |
Current liabilities |  |  |  |  |  |  |  | 4,089,000 | 7,735,000 |  |  |
Noncurrent liabilities |  |  |  |  |  |  |  | 136,568,000 | 47,608,000 |  |  |
Total Shareholders' Equity |  |  |  |  |  |  |  | 234,196,000 | 280,857,000 |  |  |
Total liabilities and equity |  |  |  |  |  |  |  | 374,854,000 | 336,200,000 |  |  |
NATs share of NAOs equity |  |  |  |  |  |  |  | 68,100,000 | 75,000,000 |  |  |
Summarized Statement of Operations information [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Operating Revenues |  |  |  |  |  |  |  | 17,697,000 | 36,372,000 | $ 52,789,000 |  |
Net Operating (Loss) Income |  |  |  |  |  |  |  | (28,543,000) | (8,372,000) | 11,262,000 |  |
Net (Loss) Income |  |  |  |  |  |  |  | (32,151,000) | (10,844,000) | $ 6,931,000 |  |
NATs portion of NAOs Net (Loss) Income |  |  |  |  |  |  |  | $ (9,300,000) | $ (2,500,000) |  |  |
Nordic American Offshore Limited [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest | 22.60% |  |  |  |  |  |  |  |  |  |  |
Common shares issued in public offering (in shares) | shares | 41,300,000 |  |  |  |  |  |  |  |  |  |  |
Public offering Price (in dollars per share) | $ / shares | $ 1.25 |  |  |  |  |  |  |  |  |  |  |
Transaction recognized in dilution loss | $ 2.6 |  |  |  |  |  |  |  |  |  |  |
Nordic American Offshore Limited [Member] | Private Placement [Member] |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Private equity placement issued amount |  |  |  | $ 250,000,000 |  |  |  |  |  |  |  |
Private equity placement participation |  |  |  | $ 65,000,000 |  |  |  |  |  |  |  |
Private equity placement participation (in shares) | shares |  |  |  | 4,333,566 |  |  |  |  |  |  |  |
Company acquired additional shares in private transaction (in shares) | shares |  | 1,571,749 |  |  |  |  |  |  |  |  |  |
Nordic American Offshore Limited [Member] | IPO [Member] |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Shares acquired (in shares) | shares |  |  | 375,000 |  |  |  |  |  |  |  |  |
Cost of shares acquired |  |  | $ 5,600,000 |  |  |  |  |  |  |  |  |

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- Definition The amount of revenue from sale of goods and services reduced by sales returns, allowances, and discounts reported by an equity method investment of the entity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721683-107760 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=66011266&loc=d3e33918-111571 + Details
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- Definition This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=66022249&loc=d3e33749-111570 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.12) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition Fair value portion of investments accounted under the equity method. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 25 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=66022186&loc=d3e32014-111567 + Details
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- Definition This item represents the net total realized and unrealized gain (loss) included in earnings for the period as a result of selling or holding marketable securities categorized as trading, available-for-sale, or held-to-maturity, including the unrealized holding gain (loss) of held-to-maturity securities transferred to the trading security category and the cumulative unrealized gain (loss) which was included in other comprehensive income (a separate component of shareholders' equity) for available-for-sale securities transferred to trading securities during the period. Additionally, this item would include any gains (losses) realized during the period from the sale of investments accounted for under the cost method of accounting and losses recognized for other than temporary impairments (OTTI) of the subject investments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (c)-(e) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27357-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.7(c),9(a)) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27405-111563 + Details
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