v3.3.1.900

DEBT (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2015
Debt Disclosure [Abstract] |
Schedule of Long-term Debt Instruments [Table Text Block] | Long-term debt consisted of the following:
|  |  |  |  | December 31,
| Maturity |  | 2015 |  | 2014
|  |  |  |  | (Thousands of Dollars)
$1.5 billion revolving credit agreement |  | 2019 |  |  | $ | 882,664 |  |  | $ | 601,496 |
4.75% senior notes |  | 2022 |  |  | 250,000 |  |  | 250,000 |
6.75% senior notes |  | 2021 |  |  | 300,000 |  |  | 300,000 |
4.80% senior notes |  | 2020 |  |  | 450,000 |  |  | 450,000 |
7.65% senior notes |  | 2018 |  |  | 350,000 |  |  | 350,000 |
7.625% subordinated notes |  | 2043 |  |  | 402,500 |  |  | 402,500 |
Gulf Opportunity Zone revenue bonds | 2038 | thru | 2041 |  | 365,440 |  |  | 365,440 |
Receivables Financing Agreement |  | 2018 |  |  | 53,500 |  |  | — |
Net fair value adjustments and unamortized discounts |  | N/A |  |  | 25,245 |  |  | 30,016 |
Total long-term debt |  |  |  |  | $ | 3,079,349 |  |  | $ | 2,749,452 |
Schedule of Maturities of Long-term Debt [Table Text Block] | The long-term debt repayments are due as follows (in thousands):
2016 - 2017 | $ | — |
2018 | 403,500 |
2019 | 882,664 |
2020 | 450,000 |
Thereafter | 1,317,940 |
Total repayments | 3,054,104 |
Net fair value adjustments and unamortized discounts | 25,245 |
Total long-term debt | $ | 3,079,349 |
Schedule of GoZone Bonds [Table Text Block] | The following table summarizes the Gulf Opportunity Zone Revenue Bonds outstanding as of December 31, 2015:
Date Issued |  | Maturity Date |  | Amount Outstanding |  | Amount of Letter of Credit |  | Amount Received from Trustee |  | Amount Remaining in Trust |  | Average Annual Interest Rate
|  |  |  | (Thousands of Dollars) |  |
June 26, 2008 |  | June 1, 2038 |  | $ | 55,440 |  |  | $ | 56,169 |  |  | $ | 55,440 |  |  | $ | — |  |  | 0.1 | %
July 15, 2010 |  | July 1, 2040 |  | 100,000 |  |  | 101,315 |  |  | 100,000 |  |  | — |  |  | 0.1 | %
October 7, 2010 |  | October 1, 2040 |  | 50,000 |  |  | 50,658 |  |  | 43,441 |  |  | 6,806 |  |  | 0.1 | %
December 29, 2010 |  | December 1, 2040 |  | 85,000 |  |  | 86,118 |  |  | 37,528 |  |  | 48,016 |  |  | 0.1 | %
August 29, 2011 |  | August 1, 2041 |  | 75,000 |  |  | 75,986 |  |  | 75,000 |  |  | — |  |  | 0.1 | %
|  | Total |  | $ | 365,440 |  |  | $ | 370,246 |  |  | $ | 311,409 |  |  | $ | 54,822 |  |  |

X
- Definition Tabular disclosure of GoZone bonds, including identification, terms, features and other information necessary to a fair presentation. + References No definition available. + Details
Name: | ns_ScheduleOfGozoneBondsTableTextBlock
Namespace Prefix: | ns_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_DebtDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer. + 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 210.5-02.22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(e),(f)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21538-112644 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644 Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28541-108399 Reference 9: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399 Reference 10: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21521-112644 + Details
Name: | us-gaap_ScheduleOfDebtInstrumentsTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the combined aggregate amount of maturities and sinking fund requirements for all long-term borrowings for each of the five years following the date of the latest balance sheet date presented. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601 + Details
Name: | us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration