v3.20.2

REVENUE FROM CONTRACTS WITH CUSTOMERS Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue recognized		$ 29,848	$ 46,757
Petroleos de Venezuela, S.A. (PDVSA) [Member]
Revenue recognized	$ 16,300

X

- Definition

Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130549-203045

+ Details

Name:	us-gaap_ContractWithCustomerLiabilityRevenueRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Details

Name:	srt_MajorCustomersAxis=ns_PetroleosdeVenezuelaS.A.PDVSAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: