Revenue from Contracts with Customers (Revenue, Remaining Performance Obligation) (Details) $ in Thousands	Mar. 31, 2021 USD ($)
Minimum [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Term of Contract	2 years
Maximum [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Term of Contract	8 years
Demand fee contracts [Member] | Mid-Stream [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Impact to Revenue	$ (1,273)
Demand fee contracts [Member] | Mid-Stream [Member] | 2021
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Impact to Revenue	(2,689)
Demand fee contracts [Member] | Mid-Stream [Member] | 2022
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Impact to Revenue	1,380
Demand fee contracts [Member] | Mid-Stream [Member] | 2023 and beyond
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Impact to Revenue	$ 36