Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Debt Instrument [Line Items]
Cash interest paid	$ 532	$ 5,366
Significant non-cash financing and investing activities:
Increase in debt from in-kind interest	6,914
Plant, equipment, and mine development acquired by note payable	407	0
Plant, equipment, and mine development additions included in accounts payable	329	3,038
Liability based restricted stock units transferred to equity	284	0
Allocate and write-off Seller's debt issuance costs	0	8,202
1.5 Lien Notes to common stock
Significant non-cash financing and investing activities:
Exchange of Seller lien notes	0	208,713
1.25 Lien Notes for Subordinated Notes
Significant non-cash financing and investing activities:
Exchange of Seller lien notes	$ 0	$ 80,000