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Asset Retirement Obligations (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Beginning balance $ 450,501 $ 459,209
Accretion 22,343 23,142
New obligations 1,249 1,154
Changes in estimates of existing obligations (1) 59,460 (21,889)
Property dispositions/obligations settled (15,166) (11,115)
Ending balance $ 518,387 $ 450,501