Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2019

Asset Retirement Obligation Disclosure [Abstract]

Schedule of Change in Asset Retirement Obligation

The following table presents the change in our gross conditional ARO (in thousands):

	December 31,
	2019			2018
Liability at January 1,	$	40,659		$	39,286
Accretion expense	2,051			2,031
Liabilities incurred	—			773
Liabilities settled	(46		)	(63		)
Revisions to cash flows	(215		)	(1,368		)
Liability at December 31,	$	42,449		$	40,659