Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 4,187,661
Accumulated depletion and depreciation	(2,610,268)
Total Property, Plant and Equipment (Notes 5)	1,577,393
Property, plant and equipment, gross		$ 3,702,958
Accumulated depletion and depreciation		(2,390,181)
Total Property, Plant and Equipment (Notes 5)	1,577,393	1,312,777
Right-of-use asset	5,700
Oil and natural gas properties
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	4,161,374	3,683,409
Proved
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	3,850,565	3,226,811
Unproved
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	310,809	456,598
Other(1)
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 26,287
Property, plant and equipment, gross		$ 19,549