INVESTMENT IN NUSTAR ENERGY Table 5 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
NuStar GP Holdings’ Equity in Earnings of NuStar Energy:
General partner interest	$ 1,237	$ 2,091	$ 5,270
General partner incentive distribution rights	45,669	43,407	43,220
General partner’s interest in earnings and incentive distributions of NuStar Energy	46,906	45,498	48,490
Common limited partner interest in earnings of NuStar Energy	7,534	13,482	34,067
Amortization of step-up in basis related to NuStar Energy’s assets and liabilities	(2,884)	(2,884)	(2,884)
Equity in earnings of NuStar Energy	$ 51,556	$ 56,096	$ 79,673