XML 34 R52.htm IDEA: XBRL DOCUMENT
v2.4.0.6

OTHER NON-CURRENT ASSETS (Details) (USD $) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2011 | Dec. 31, 2010
OTHER NON-CURRENT ASSETS [Abstract] |  |
Working Capital, cooperative arrangements | $ 0 | $ 22,034,000
Financial Charges | 490,000 | 1,143,000
Total | 490,000 | 23,177,000
Initial funding per vessel | $ 200,000 |
Number of months working capital is to be repaid (in months) | 6 |

X
- Definition The amount, per vessel, added to the value of bunkers on board the company's vessels at the time of delivery to the Cooperative Arrangement to obtain the amount of working capital under cooperative arrangements. + References No definition available. + Details
Name: | nat_InitialFundingPerVessel
Namespace Prefix: | nat_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Number of months working capital is to be repaid. + References No definition available. + Details
Name: | nat_NumberOfMonthsWorkingCapitalIsToBeRepaid
Namespace Prefix: | nat_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition The value of bunkers on board on the company's vessels at time of delivery plus initial funding in certain dollar amount per vessel, classified as noncurrent assets. + References No definition available. + Details
Name: | nat_WorkingCapitalCooperativeArrangementsNoncurrent
Namespace Prefix: | nat_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Net amount of long-term deferred finance costs capitalized at the end of the reporting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.17) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 21 -Paragraph 16 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 17 -Article 5 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28555-108399 + Details
Name: | us-gaap_DeferredFinanceCostsNoncurrentNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Aggregate carrying amount, as of the balance sheet date, of noncurrent assets not separately disclosed in the balance sheet. Noncurrent assets are expected to be realized or consumed after one year (or the normal operating cycle, if longer). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 17 -Article 5 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 210.5-02.17) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_OtherAssetsNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_OtherAssetsNoncurrentDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration