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Asset Retirement Obligation (Tables)
 12 Months Ended
Dec. 31, 2020
Asset Retirement Obligation Disclosure [Abstract]  
Information Related to Asset Retirement Obligations The following table reflects information related to our asset retirement obligations:

 

Balance at December 31, 2018

 

$

222,989

 

Additions to asset retirement obligations

 

 

2,529

 

Accretion expense

 

 

4,260

 

Liabilities settled

 

 

(3,641

)

Balance at December 31, 2019

 

$

226,137

 

Additions to asset retirement obligations

 

 

658

 

Accretion expense

 

 

4,135

 

Liabilities settled

 

 

(8,054

)

Balance at December 31, 2020

 

$

222,876