CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Equity in earnings of NuStar Energy L.P.	$ 56,096	$ 79,673	$ 65,380
General and administrative expenses
Third parties	(2,258)	(3,338)	(3,396)
Related party	(788)	0	0
Total general and administrative expenses	(3,046)	(3,338)	(3,396)
Other income (expense), net	3,021	(2,333)	(1,458)
Interest expense, net	(1,069)	(893)	(885)
Income before income tax benefit (expense)	55,002	73,109	59,641
Income tax benefit (expense)	66	(901)	1,786
Net income	55,068	72,208	61,427
Other comprehensive (loss) income:
Share of NuStar Energy L.P.’s other comprehensive loss	(685)	(3,107)	(665)
Pension and other postretirement benefit plan adjustments	(4,525)	218	(14,051)
Total other comprehensive loss	(5,210)	(2,889)	(14,716)
Comprehensive income	$ 49,858	$ 69,319	$ 46,711
Basic net income per unit	$ 1.28	$ 1.68	$ 1.44
Diluted net income per unit	$ 1.28	$ 1.68	$ 1.44
Weighted-average number of basic units outstanding	42,932,320	42,914,297	42,719,217
Weighted-average number of diluted units outstanding	42,932,320	42,914,297	42,742,202