XML 37 R23.htm IDEA: XBRL DOCUMENT v3.22.2.2
Nature of Operations and Basis of Presentation (Narrative) (Details)
$ in Thousands
3 Months Ended 9 Months Ended
May 02, 2022
USD ($)
Sep. 30, 2022
USD ($)
Jun. 30, 2022
USD ($)
Sep. 30, 2021
USD ($)
Sep. 30, 2022
USD ($)
segment
Sep. 30, 2021
USD ($)
Long-term Purchase Commitment [Line Items]            
Number of operating segments | segment         3  
Gain on contract termination   $ 0   $ 10,333 $ 14,000 $ 10,333
Expenditures for property, plant and equipment and acquisition of mineral interests   17,086   $ 19,407 42,004 $ 35,534
Coal Mining | Falkirk            
Long-term Purchase Commitment [Line Items]            
Total gain on contract termination     $ 30,900      
Gain on contract termination $ 14,000          
Fair value gained from contract termination 4,100          
Fair value of privately-held company 12,800          
Investment $ 5,000          
Minerals Management | Texas Portion, Permian Basin and Wyoming Portion, Powder River            
Long-term Purchase Commitment [Line Items]            
Expenditures for property, plant and equipment and acquisition of mineral interests         $ 12,300  
Payments to acquire royalty interests   $ 11,400