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Contingencies - Narratives (Details) - USD ($) | Dec. 31, 2018 | Dec. 31, 2017
--- | --- | ---
Loss Contingencies [Line Items] |  |
Long-term debt - affiliate | $ 86,478,000 | $ 0
Minimum |  |
Loss Contingencies [Line Items] |  |
Loss Contingency, Estimate of Possible Loss | 65,000,000 |
Maximum |  |
Loss Contingencies [Line Items] |  |
Loss Contingency, Estimate of Possible Loss | $ 90,000,000 |
Profit Units | LTIP |  |
Loss Contingencies [Line Items] |  |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | 30,000 |
Threshold Value | $ 855,000,000 |

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