Commitments and Contingencies (Details) - USD ($) $ in Millions			1 Months Ended		3 Months Ended		6 Months Ended
	Feb. 25, 2019	Feb. 17, 2017	May 31, 2018	Apr. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Delivery Of Natural Gas And Oil Production To Third Parties
Long-term Purchase Commitment [Line Items]
Volume requirement commitment					$ 163.4		$ 163.4
Payment for volume requirement agreement					6.1	$ 5.1	12.9	$ 9.1
Corporate Joint Venture | San Mateo Midstream
Commitments and Contingencies (Textual) [Abstract]
Contractual obligation					183.8		$ 183.8
Contract agreement term	15 years
Rustler Breaks and Wolf Asset Area | Corporate Joint Venture | San Mateo Midstream
Commitments and Contingencies (Textual) [Abstract]
Term of contractual obligation		15 years
Rustler Breaks Asset Area | Corporate Joint Venture | San Mateo Midstream
Commitments and Contingencies (Textual) [Abstract]
Term of contractual obligation		15 years
Natural Gas Transportation and Fractionation Agreement | Eddy County
Commitments and Contingencies (Textual) [Abstract]
Agreement term							7 years
Contractual obligation					132.3		$ 132.3
16-Year Fixed Fee Natural Gas Transportation Agreement | Eddy County
Commitments and Contingencies (Textual) [Abstract]
Agreement term				16 years
Contractual obligation					56.8		56.8
2019 10-Year Fixed Fee Natural Gas Transportation Agreement | Eddy County
Commitments and Contingencies (Textual) [Abstract]
Agreement term			10 years
Contractual obligation					202.3		202.3
Operational Agreements | San Mateo Midstream
Commitments and Contingencies (Textual) [Abstract]
Contractual obligation	$ 363.8
Engineering, Procurement, Construction And Installation Of Processing Plant | San Mateo Midstream
Commitments and Contingencies (Textual) [Abstract]
Contractual obligation					80.1		80.1
Payments made under agreement					8.3
Remaining obligation					$ 71.8		$ 71.8