Revolving Credit Facilities (Details)	1 Months Ended		9 Months Ended
	Apr. 30, 2020 USD ($)	Apr. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Oct. 29, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jun. 30, 2019 USD ($)
Short-term Debt [Line Items]
Number of days outstanding, prior to springing maturity date			91 days
Value of proved reserves, percentage to mortgage			85.00%
Value of proved developing producing reserves, percentage to mortgage			85.00%
Federal Funds Open Rate
Short-term Debt [Line Items]
Basis spread on variable rate			0.50%
Federal Funds Open Rate | Midstream
Short-term Debt [Line Items]
Basis spread on variable rate			0.50%
One-Month LIBOR
Short-term Debt [Line Items]
Basis spread on variable rate			1.00%
One-Month LIBOR | Midstream
Short-term Debt [Line Items]
Basis spread on variable rate			1.00%
One-Month LIBOR | Minimum
Short-term Debt [Line Items]
Basis spread on variable rate			0.75%
One-Month LIBOR | Minimum | Midstream
Short-term Debt [Line Items]
Basis spread on variable rate			0.50%
One-Month LIBOR | Maximum
Short-term Debt [Line Items]
Basis spread on variable rate			1.75%
One-Month LIBOR | Maximum | Midstream
Short-term Debt [Line Items]
Basis spread on variable rate			1.50%
LIBOR | Minimum
Short-term Debt [Line Items]
Basis spread on variable rate			1.75%
LIBOR | Minimum | Midstream
Short-term Debt [Line Items]
Basis spread on variable rate			1.50%
LIBOR | Maximum
Short-term Debt [Line Items]
Basis spread on variable rate			2.75%
LIBOR | Maximum | Midstream
Short-term Debt [Line Items]
Basis spread on variable rate			2.50%
6.50% Senior Notes due March 2026
Short-term Debt [Line Items]
Debt instrument, face amount			$ 400,000,000		$ 400,000,000
Stated rate, debt instrument			6.50%
6.50% Senior Notes due March 2026 | Midstream
Short-term Debt [Line Items]
Stated rate, debt instrument			6.50%
6.50% Senior Notes due March 2026 | Minimum | Midstream
Short-term Debt [Line Items]
Debt instrument, face amount			$ 150,000,000
6.50% Senior Notes due March 2026 | Maximum | Midstream
Short-term Debt [Line Items]
Debt instrument, face amount			150,000,000
Revolving Credit Facility
Short-term Debt [Line Items]
Debt instrument, face amount		$ 2,100,000,000				$ 160,000,000
Accordion feature, increased commitment		$ 3,000,000,000
Net leverage ratio		3.00
Percentage of aggregate commitments available under credit facility		15.00%
Initial borrowing base	$ 1,900,000,000
Letters of credit aggregate sub-limit		$ 650,000,000
Basket for dividends and distributions, annual limit of available cash	$ 150,000,000
Minimum threshold to activate springing maturity date			$ 500,000,000
Minimum current ratio			1.00
Borrowings outstanding			$ 410,000,000		661,000,000
Letters of credit outstanding			185,272,000		204,726,000
Borrowings and issuance of letters of credit remaining capacity			1,304,728,000		1,234,274,000
Revolving Credit Facility | Subsequent Event
Short-term Debt [Line Items]
Initial borrowing base				$ 1,900,000,000
Revolving Credit Facility | Midstream
Short-term Debt [Line Items]
Letters of credit aggregate sub-limit		600,000,000
Borrowings outstanding			343,000,000		311,750,000
Letters of credit outstanding			30,000
Borrowings and issuance of letters of credit remaining capacity			$ 256,970,000
Increase in available borrowings		$ 250,000,000
Secured leverage ratio			3.00
Total leverage ratio			4.00
Pro forma availability of commitments, percentage			20.00%
Basket for repurchase of LP units tied to Available Cash, annual limit			$ 150,000,000
Basket for repurchase of LP units tied to Available Cash, lifetime limit			200,000,000
Maximum borrowing capacity, letters of credit			$ 100,000,000
Interest coverage ratio			2.50
Revolving credit available for borrowing					$ 288,250,000
Revolving Credit Facility | Minimum | Midstream
Short-term Debt [Line Items]
Total leverage ratio			4.75
Maximum net leverage ratio			5.25
Revolving Credit Facility | Maximum
Short-term Debt [Line Items]
Net leverage ratio			4.00
Revolving Credit Facility | Maximum | Midstream
Short-term Debt [Line Items]
Secured leverage ratio			3.50
Total leverage ratio			5.25
Maximum net leverage ratio			5.50