Subsequent Events (Details)			2 Months Ended	12 Months Ended
	Oct. 17, 2018 USD ($) a well location shares	Oct. 08, 2018 USD ($) a	Dec. 31, 2018 USD ($) $ / shares	Oct. 17, 2019 USD ($)	Nov. 06, 2018 USD ($)	Nov. 02, 2018 USD ($)	Sep. 30, 2018 $ / shares	May 23, 2018 USD ($)	Dec. 31, 2017 $ / shares	May 09, 2017 USD ($)
Subsequent Event [Line Items]
Preferred stock, par value (in dollars per share) | $ / shares							$ 0.001		$ 0.001
Subsequent Event
Subsequent Event [Line Items]
Number of acres acquired | a	20,800	3,899
Working interest acquired (as a percent)		100.00%
Number of acres sold | a		1,222
Working interest sold (as a percent)		39.00%
Payments to acquire acreage	$ 950,000,000	$ 27,800,000
Number of operated horizontal drilling locations | location	488
Number of non-operated horizontal drilling locations | location	349
Number of existing vertical and horizontal wells, gross | well	125
Number of existing vertical and horizontal wells, net | well	67.4
Cash payments to acquire oil and gas property	$ 650,000,000
Amount of equity issued	$ 300,000,000
Shares issued in transaction | shares	32,315,695
Line of Credit | Subsequent Event
Subsequent Event [Line Items]
Line of credit, borrowing base						$ 550,000,000
Line of Credit | EEH Credit Agreement
Subsequent Event [Line Items]
Line of credit, borrowing base								$ 225,000,000.0		$ 185,000,000.0
Line of Credit | EEH Credit Agreement | Subsequent Event
Subsequent Event [Line Items]
Line of credit, borrowing base					$ 275,000,000
New Credit Facility | Subsequent Event
Subsequent Event [Line Items]
Line of credit, borrowing base	$ 475,000,000
Bridge Facility | Subsequent Event
Subsequent Event [Line Items]
Line of credit, borrowing base	$ 500,000,000
Class B Common Stock | Subsequent Event
Subsequent Event [Line Items]
Shares issued in transaction | shares	32,315,695
Scenario, Forecast | Senior Notes | Subsequent Event
Subsequent Event [Line Items]
Proceeds from Issuance of Unsecured Debt				$ 500,000,000
Scenario, Forecast | Convertible Preferred Stock | Subsequent Event
Subsequent Event [Line Items]
Proceeds from issuance of preferred stock			$ 225,000,000
Preferred stock, par value (in dollars per share) | $ / shares			$ 0.001
Scenario, Forecast | Class A Common Stock | Subsequent Event
Subsequent Event [Line Items]
Cash from sale of stock			$ 30,000,000