ASSET RETIREMENT OBLIGATIONS (Tables)	9 Months Ended
Sep. 30, 2021
ASSET RETIREMENT OBLIGATIONS [Abstract]
Asset Retirement Obligations Operating Costs	Three Months Ended Nine Months Ended September 30 September 30in thousands2021 2020 2021 2020 ARO Operating Costs Accretion$ 3,341 $ 3,115 $ 9,796 $ 9,270 Depreciation 2,916 2,123 8,241 6,022 Total$ 6,257 $ 5,238 $ 18,037 $ 15,292
Reconciliations of Asset Retirement Obligations	Three Months Ended Nine Months Ended September 30 September 30in thousands2021 2020 2021 2020 Asset Retirement Obligations Balance at beginning of period$ 286,435 $ 263,748 $ 283,163 $ 210,323 Liabilities incurred 10,712 353 11,650 353 Liabilities settled (5,321) (2,459) (10,274) (11,047) Accretion expense 3,341 3,115 9,796 9,270 Revisions, net 3,165 (5,809) 3,997 50,049 Balance at end of period$ 298,332 $ 258,948 $ 298,332 $ 258,948

Tabular disclosure of the changes in carrying amount of a liability for asset retirement obligations, for changes such as new obligations, changes in estimates of existing obligations, spending on existing obligations, property dispositions, and foreign currency translation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 30
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13201-110859

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