Properties and Equipment (Tables)

6 Months Ended

Jun. 30, 2021

Oil and Gas Property [Abstract]

Property, Plant and Equipment

The following table presents the components of properties and equipment, net of accumulated depreciation, depletion and amortization (“DD&A”) as of the dates indicated:

	June 30, 2021		December 31, 2020
	(in thousands)
Properties and equipment, net:
Crude oil and natural gas properties
Proved	$	7,875,257	$	7,523,639
Unproved	351,626		350,677
Total crude oil and natural gas properties	8,226,883		7,874,316
Equipment and other	63,861		65,027
Land and buildings	17,664		24,299
Construction in progress	470,021		523,550
Properties and equipment, at cost	8,778,429		8,487,192
Accumulated DD&A	(3,931,747)		(3,627,993)
Properties and equipment, net	$	4,846,682	$	4,859,199

Schedule of Aging of Capitalized Exploratory Well Costs [Table Text Block]

The following table presents the capitalized exploratory well cost pending determination of proved reserves and included in properties and equipment for the periods presented:

	Six Months Ended June 30,		Year Ended December 31, 2020
	(in thousands, except for number of wells)
Beginning balance	$	7,459	$	16,078
Additions to capitalized exploratory well costs pending the determination of proved reserves	5,521		11,770
Reclassifications to proved properties	—		(20,389)
Ending balance	$	12,980	$	7,459
Number of wells pending determination at period-end	2		2