RELATED PARTY TRANSACTIONS Narrative (Details)	3 Months Ended
Mar. 31, 2018
Related Party Transactions [Abstract]
Administrative fees, description	The Amended GP Services Agreement provides that we will furnish administrative services necessary to conduct the business of NuStar GP Holdings. NuStar GP Holdings will compensate us for these services through an annual fee of $1.0 million, subject to adjustment based on the annual merit increase percentage applicable to our employees for the most recently completed fiscal year and for changes in level of service. The Amended GP Services Agreement will expire on March 1, 2020 and will automatically renew for successive two-year terms, unless terminated by either party.

Description of the nature of payments to a managing member or general partner, affiliate of a managing member or general partner, or affiliate of a limited liability company (LLC) or limited partnership (LP) for administrative services provided to the LLC or LP, for example, but is not limited to, salaries, rent, or other overhead costs. Includes a description of the services performed and the amount reimbursed for such services.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Name:	us-gaap_AdministrativeFeesDescription
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration