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Variable Interest Entity Arrangements (Details)
3 Months Ended
Mar. 31, 2020
USD ($)
Variable Interest Entity [Line Items]  
Methodology for Determining Whether Entity is Primary Beneficiary The two variable interests applicable to Unit include the 50% equity investment in Superior and the MSA. The MSA gives us the power to direct the activities that most significantly affect Superior's operating performance. The MSA is a separate variable interest. Unit through the MSA has the power to direct Superior’s most significant activities; reciprocally the equity investors lack the power to direct the activities that most affect the entity’s economic performance. Because of this, Unit is considered the primary beneficiary.
Superior Pipeline Company, L.L.C. [Member]  
Variable Interest Entity [Line Items]  
Date Involvement Began Apr. 03, 2018
Lack of Recourse Superior's creditors have no recourse to our general credit.
SP Investor Holdings, LLC [Member] | Superior Pipeline Company, L.L.C. [Member]  
Variable Interest Entity [Line Items]  
Ownership Percentage 50.00%
SPC Midstream Operating, L.L.C. [Member] | Superior Pipeline Company, L.L.C. [Member]  
Variable Interest Entity [Line Items]  
Monthly service fee $ 260,560