CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Equity in earnings of NuStar Energy L.P.	$ 27,522	$ 14,390
General and administrative expenses	(951)us-gaap_GeneralAndAdministrativeExpense	(872)us-gaap_GeneralAndAdministrativeExpense
Other income, net	462us-gaap_OtherNonoperatingIncomeExpense	17us-gaap_OtherNonoperatingIncomeExpense
Interest expense, net	(213)us-gaap_InterestExpenseDebt	(222)us-gaap_InterestExpenseDebt
Income before income tax (expense) benefit	26,820	13,313
Income tax (expense) benefit	(15)us-gaap_IncomeTaxExpenseBenefit	333us-gaap_IncomeTaxExpenseBenefit
Net income	26,805us-gaap_NetIncomeLoss	13,646us-gaap_NetIncomeLoss
Comprehensive income	$ 23,540us-gaap_ComprehensiveIncomeNetOfTax	$ 12,698us-gaap_ComprehensiveIncomeNetOfTax
Basic net income per unit	$ 0.62us-gaap_EarningsPerShareBasic	$ 0.32us-gaap_EarningsPerShareBasic
Diluted net income per unit	$ 0.62us-gaap_EarningsPerShareDiluted	$ 0.32us-gaap_EarningsPerShareDiluted
Weighted-average number of basic units outstanding	42,913,277	42,656,281
Weighted-average number of diluted units outstanding	42,913,277	42,656,281

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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