MEMBERS' EQUITY Table 1 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ (13,874)
Other comprehensive income (loss)	3,052	$ (5,210)	$ (2,889)
Ending Balance	(10,822)	(13,874)
Share of NuStar Energy's Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(13,874)	(13,189)	(10,082)
Other comprehensive income (loss) before reclassification adjustments	3,052	(685)	(3,107)
Amounts reclassified to general and administrative expenses (a)		0	0
Employee Transfer		0
Other comprehensive income (loss)		(685)	(3,107)
Ending Balance	(10,822)	(13,874)	(13,189)
Pension and Other Postretirement Benefit Plan Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	0	4,525	4,307
Other comprehensive income (loss) before reclassification adjustments	0	0	1,312
Amounts reclassified to general and administrative expenses (a)		(324)	(1,094)
Employee Transfer		(4,201)
Other comprehensive income (loss)		(4,525)	218
Ending Balance	0	0	4,525
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(13,874)	(8,664)	(5,775)
Other comprehensive income (loss) before reclassification adjustments	3,052	(685)	(1,795)
Amounts reclassified to general and administrative expenses (a)		(324)	(1,094)
Employee Transfer		(4,201)
Other comprehensive income (loss)	3,052	(5,210)	(2,889)
Ending Balance	$ (10,822)	$ (13,874)	$ (8,664)