Related Party Transactions - Summary of Reimbursements (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Related Party Transaction [Line Items]
General and administrative expenses	$ 3,388	$ 3,621	$ 7,498	$ 7,534
Quintana Minerals | Affiliated Entity
Related Party Transaction [Line Items]
Accounts Payable, Related Parties, Current	400		400		$ 400
Western Pocahontas Properties Limited Partnership | Affiliated Entity
Related Party Transaction [Line Items]
Accounts Payable, Related Parties, Current	300		300		$ 300
Operating and maintenance expenses	1,000	100	1,200	200
Western Pocahontas Properties and Quintana Minerals Corporation | Affiliated Entity
Related Party Transaction [Line Items]
Operating and maintenance expenses	1,645	1,596	3,252	3,300
General and administrative expenses	$ 1,115	$ 1,119	$ 2,301	$ 2,321