Properties and Equipment (Tables)

3 Months Ended

Mar. 31, 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:

	March 31, 2021		December 31, 2020
	(in thousands)
Properties and equipment, net:
Crude oil and natural gas properties
Proved	$	7,650,594	$	7,523,639
Unproved	350,993		350,677
Total crude oil and natural gas properties	8,001,587		7,874,316
Equipment and other	64,900		65,027
Land and buildings	17,665		24,299
Construction in progress	519,931		523,550
Properties and equipment, at cost	8,604,083		8,487,192
Accumulated DD&A	(3,771,285)		(3,627,993)
Properties and equipment, net	$	4,832,798	$	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:

	Three Months Ended March 31,		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	1,219		11,770
Reclassifications to proved properties	—		(20,389)
Ending balance	$	8,678	$	7,459
Number of wells pending determination at period-end	2		2