Investments (Details) $ in Thousands			1 Months Ended			3 Months Ended		4 Months Ended	6 Months Ended
	Nov. 22, 2016 USD ($)	Jul. 05, 2016 USD ($)	May 31, 2018 a MMcf	Nov. 30, 2016 USD ($)	Jul. 31, 2016 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Apr. 30, 2018 MMcf	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Schedule of Equity Method Investments [Line Items]
Capital investments						$ 127,774			$ 127,774		$ 125,059
Earnings (loss) from equity investments						3,111	$ 1,042		7,383	$ 1,524
Amortization of intangible assets						3,365	$ 3,412		6,730	6,824
Distributions received									13,101	$ 3,684
Carnero Gathering, Joint Venture
Schedule of Equity Method Investments [Line Items]
Ownership interest (as a percent)		50.00%			50.00%
Payments to acquire interest in joint venture		$ 37,000			$ 37,000				123,700
Assumption of capital commitments in joint venture		$ 7,400			7,400
Daily processing capacity | MMcf			400
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%			50.00%
Payments to acquire interest in joint venture	$ 55,500			$ 55,500
Assumption of capital commitments in joint venture	$ 24,500			24,500
Carnero P&G, Joint Venture
Schedule of Equity Method Investments [Line Items]
Ownership interest (as a percent)			50.00%
Payments to acquire interest in joint venture									123,700
Daily processing capacity | MMcf			460					260
Acres dedicated for gathering | a			315,000
Earnings (loss) from equity investments						3,400			8,000
Amortization of intangible assets						$ 300			$ 600
Sanchez Energy
Schedule of Equity Method Investments [Line Items]
Assumption of capital commitments in joint venture				$ 24,200
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 P&G, Joint Venture
Schedule of Equity Method Investments [Line Items]
Ownership interest (as a percent)			50.00%
Equity interests in plant transferred to joint venture (as a percent)			100.00%