Variable Interest Entity Arrangements (Details) - USD ($) $ in Thousands		1 Months Ended			9 Months Ended
	Nov. 01, 2021	Oct. 31, 2021	Jul. 31, 2021	Apr. 30, 2021	Sep. 30, 2021	Apr. 03, 2018
Variable Interest Entity [Line Items]
Liquidation IRR Hurdle					7.00%
Variable Interest Investment						$ 300,000
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. Under the MSA, Unit 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.
Distributions paid			$ 7,700	$ 24,700
Liquidation distributions					$ 362,600
Subsequent Event [Member]
Variable Interest Entity [Line Items]
Distributions paid		$ 13,900
VIE
Variable Interest Entity [Line Items]
Date Involvement Began					Apr. 03, 2018
VIE | Subsequent Event [Member]
Variable Interest Entity [Line Items]
Asset Acquisition, Consideration Transferred	$ 13,000
SPC Midstream Operating, L.L.C. [Member] | VIE
Variable Interest Entity [Line Items]
Monthly service fee					$ 300
SP Investor Holdings, LLC [Member] | VIE
Variable Interest Entity [Line Items]
Ownership Percentage					50.00%