Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2019

Asset Retirement Obligation Disclosure [Abstract]

Schedule of change in asset retirement obligation

During 2019 and 2018, our overall asset retirement obligation changed as follows (in thousands):

	2019			2018
Beginning balance	$	69,350		$	67,100
Accretion	4,605			4,359
Changes in estimates of existing obligations (1)	17,307			(2,095		)
Property dispositions/obligations settled	(11		)	(14		)
Ending balance	$	91,251		$	69,350

(1)

Changes in estimates of existing obligations are primarily due to the annual review process, which considers various factors including inflation rates, current estimates for removal costs, the estimated remaining life of assets, and discount rates.