XML 55 R44.htm IDEA: XBRL DOCUMENT v3.22.2
Commitments and Contingencies (Details) - USD ($)
3 Months Ended 6 Months Ended
Jun. 30, 2022
Mar. 31, 2022
Jun. 30, 2021
Jun. 30, 2022
Jun. 30, 2021
Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]            
Settlement proceeds   $ 700,000 $ 0   $ 0  
Throughput obligation $ 0     $ 0   $ 0
Coal royalty expense $ 48,700,000   $ 15,700,000 $ 73,900,000 $ 28,400,000