Investments (Details) - USD ($)	1 Months Ended		3 Months Ended
	Nov. 30, 2016	Jul. 31, 2016	Mar. 31, 2020	Mar. 31, 2019
Schedule of Equity Method Investments [Line Items]
Earnings (losses) from equity investments			$ (1,202,000)	$ 1,442,000
Amortization of intangible assets			3,364,000	3,365,000
Distributions received			1,615,000	4,658,000
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		$ 37,000,000	124,100,000
Assumption of capital commitments in joint venture		7,400,000
Carnero Gathering, Joint Venture | Customer Relationships
Schedule of Equity Method Investments [Line Items]
Intangible asset, fair value		$ 13,000,000
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	$ 55,500,000
Assumption of capital commitments in joint venture	$ 24,500,000
Carnero G&P, Joint Venture
Schedule of Equity Method Investments [Line Items]
Payments to acquire interest in joint venture			124,100,000
Earnings (losses) from equity investments			(900,000)
Amortization of intangible assets			300,000
Distributions received			1,600,000
Sanchez Energy
Schedule of Equity Method Investments [Line Items]
Earnout payments			$ 0	$ 18,900
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%