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Investments (Details) $ in Thousands	1 Months Ended				3 Months Ended		9 Months Ended
Investments (Details) $ in Thousands	May 31, 2018 a mi MMcf	Apr. 30, 2018 MMcf	Nov. 30, 2016 USD ($)	Jul. 31, 2016 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Schedule of Equity Method Investments [Line Items]
Acquisitions, earnout and capital investments					$ 128,141		$ 128,141		$ 127,899
Earnings (loss) from equity investments					780	$ 2,313	3,013	$ 9,696
Amortization of intangible assets					3,365	$ 3,365	10,095	10,095
Distributions received							12,368	18,572
Carnero Gathering, Joint Venture
Schedule of Equity Method Investments [Line Items]
Ownership interest (as a percent)				50.00%
Payments to acquire interest in joint venture				$ 37,000			124,100
Assumption of capital commitments in joint venture				7,400
Daily processing capacity \| MMcf	400
Acres dedicated for gathering \| a	315,000
Carnero Gathering, Joint Venture \| Customer Relationships
Schedule of Equity Method Investments [Line Items]
Intangible asset, fair value				$ 13,000
Agreement term (in years)				15 years
Carnero Processing, Joint Venture
Schedule of Equity Method Investments [Line Items]
Ownership interest (as a percent)			50.00%
Payments to acquire interest in joint venture			$ 55,500
Assumption of capital commitments in joint venture			$ 24,500
Carnero G&P, Joint Venture
Schedule of Equity Method Investments [Line Items]
Ownership interest (as a percent)	50.00%
Payments to acquire interest in joint venture							124,100
Daily processing capacity \| MMcf	460	260
Number of miles of high pressure natural gas gathering pipelines \| mi	45
Earnings (loss) from equity investments					1,100		3,900
Amortization of intangible assets					$ 300		900
Distributions received							12,400
Sanchez Energy \| Carnero Gathering, Joint Venture
Schedule of Equity Method Investments [Line Items]
Earnout payments							$ 32,100	$ 0
Targa \| Carnero Gathering, Joint Venture
Schedule of Equity Method Investments [Line Items]
Ownership interest (as a percent)				50.00%
Targa \| Carnero Processing, Joint Venture
Schedule of Equity Method Investments [Line Items]
Ownership interest (as a percent)			50.00%
Targa \| Carnero G&P, Joint Venture
Schedule of Equity Method Investments [Line Items]
Ownership interest (as a percent)	100.00%