Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2020

Asset Retirement Obligation Disclosure [Abstract]

Schedule of Changes in Asset Retirement Obligation

The following table documents the changes in the Company’s asset retirement obligation during the years ended December 31 (dollars in thousands):

	2020			2019			2018
Asset retirement obligation at beginning of year	$	20,338		$	18,266		$	17,482
Liabilities incurred		(2,315	)		2,699			—
Liabilities settled		(1,645	)		(1,503	)		(66	)
Accretion expense		816			876			850
Asset retirement obligation at end of year	$	17,194		$	20,338		$	18,266