Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2020

Asset Retirement Obligation Disclosure [Abstract]

Reconciliation of Asset Retirement Obligations which are Included in Other Liabilities

The following table reconciles our AROs as of the dates presented, which are included in the “Other liabilities” caption on our Consolidated Balance Sheets: 

	Year Ended December 31,
	2020		2019
Balance at beginning of period	$	4,934	$	4,314
Changes in estimates	33		(2)
Liabilities incurred	121		290
Liabilities settled	—		(67)
Acquisitions of properties	16		83
Accretion expense	357		316
Balance at end of period	$	5,461	$	4,934