Debt Credit Agreement (Details) - USD ($)	Jun. 30, 2019	Apr. 30, 2019	Dec. 19, 2018
Revolving Credit Facility | Third Amended Credit Agreement
Debt Instrument [Line Items]
Increase in borrowing base		$ 900,000,000.0
Maximum borrowing commitment	$ 500,000,000.0
Maximum facility amount	1,500,000,000
Line of Credit | San Mateo Credit Facility
Debt Instrument [Line Items]
Maximum borrowing commitment	$ 325,000,000.0		$ 250,000,000.0
Line of credit, accordian feature			$ 400,000,000.0