| Schedule of Net Income Per Unit [Text Block] |
The following table details the calculation of net income per common unit: | | | | | | | | | | | | | | Year Ended December 31, | | 2017 | | 2016 | | 2015 | | (Thousands of Dollars, Except Per Unit Data) | Net income attributable to NuStar Energy L.P. | $ | 147,964 |
| | $ | 150,003 |
| | $ | 306,720 |
| Less: Distributions to general partner (including incentive distribution rights) | 54,921 |
| | 51,284 |
| | 51,064 |
| Less: Distributions to common limited partners | 407,681 |
| | 342,598 |
| | 341,140 |
| Less: Distributions to preferred limited partners | 40,448 |
| | 1,925 |
| | — |
| Less: Distribution equivalent rights to restricted units | 2,965 |
| | 2,697 |
| | — |
| Distributions in excess of earnings | $ | (358,051 | ) | | $ | (248,501 | ) | | $ | (85,484 | ) | | | | | | | Net income attributable to common units: | | | | | | Distributions to common limited partners | $ | 407,681 |
| | $ | 342,598 |
| | $ | 341,140 |
| Allocation of distributions in excess of earnings | (350,890 | ) | | (243,530 | ) | | (83,774 | ) | Total | $ | 56,791 |
| | $ | 99,068 |
| | $ | 257,366 |
| | | | | | | Basic weighted-average common units outstanding | 88,825,964 |
| | 78,080,484 |
| | 77,886,078 |
| | | | | | | Diluted common units outstanding: | | | | | | Basic weighted-average common units outstanding | 88,825,964 |
| | 78,080,484 |
| | 77,886,078 |
| Effect of dilutive potential common units | — |
| | 32,518 |
| | — |
| Diluted weighted-average common units outstanding | 88,825,964 |
| | 78,113,002 |
| | 77,886,078 |
| | | | | | | Basic and diluted net income per common unit | $ | 0.64 |
| | $ | 1.27 |
| | $ | 3.30 |
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