Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2021

Asset Retirement Obligation Disclosure [Abstract]

Summary of Changes in Asset Retirement Obligation Liability Balances

The components of the changes in the asset retirement obligation liabilities for the periods stated were as follows:

(Dollars in thousands)	Short-Term Portion		Long-Term Portion		Total
Balance at December 31, 2019	$	90	$	6,061	$	6,151
Accretion	(38)		509		471
Amounts paid	(352)		—		(352)
Additions	169		1,185		1,354
Reclassifications	466		(466)		—
Balance at December 31, 2020	335		7,289		7,624
Accretion	(125)		741		616
Amounts paid	(334)		—		(334)
Additions	(129)		(1,292)		(1,421)
Reclassifications	383		(383)		—
Balance at December 31, 2021	$	130	$	6,355	$	6,485