Asset Retirement Obligations (Tables)

9 Months Ended

Sep. 30, 2019

Asset Retirement Obligations [Abstract]

Summary of Changes in Asset Retirement Obligations

(in thousands)	Nine Months Ended September 30, 2019		Year Ended December 31, 2018
Beginning balance	$	14,816	$	20,163
Accretion		601		1,180
Additions		292		—
Revisions		—		(6,527)
Ending balance	$	15,709	$	14,816