Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2019

Asset Retirement Obligation Disclosure [Abstract]

Reconciliation of Beginning and Ending Aggregate Carrying Amounts of Asset Retirement Obligations

The following table presents the balance and activity of the Company’s asset retirement obligations (in thousands):

	Year Ended December 31,
	2019		2018		2017
Beginning balance	$	60,064	$	77,544	$	106,481
Liability incurred upon acquiring and drilling wells	2,771		7,079		1,336
Revisions in estimated cash flows(1)	12,208		870		(28,565)
Liability settled or disposed in current period(2)	(5,379)		(31,967)		(11,308)
Accretion	5,352		6,538		9,600
Ending balance	75,016		60,064		77,544
Less: current portion	22,119		25,393		41,017
Asset retirement obligations, net of current	$	52,897	$	34,671	$	36,527

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(1) Revisions for the years ended December 31, 2019, 2018 and 2017 relate primarily to changes in estimated well lives due to changes in oil and natural gas prices and changes in plugging cost estimates.

(2) Liability settled or disposed for the year ended December 31, 2018 includes $26.9 million associated with the Permian  Properties sold in November 2018.