XML 51 R40.htm IDEA: XBRL DOCUMENT v3.25.2
Commitments and Contingencies - Narrative (Details) - USD ($)
$ in Millions
6 Months Ended 12 Months Ended
Jun. 30, 2025
Dec. 31, 2024
Other Commitments [Line Items]    
Restricted cash, long-term $ 8.5 $ 8.5
Supply agreement performance bond 4.0  
Contract with customer, liability 2.4  
Tinuum Group, LLC    
Other Commitments [Line Items]    
Liabilities assumed $ 1.7 $ 1.7
Tinuum Group, LLC    
Other Commitments [Line Items]    
Limited guarantees (as percent) 50.00%  
Five Forks Mine    
Other Commitments [Line Items]    
Surety bond amount $ 7.5  
Corbin Facilities    
Other Commitments [Line Items]    
Surety bond amount 3.0  
West Virginia ("Mine 4")    
Other Commitments [Line Items]    
Surety bond amount 0.7  
Restricted cash, long-term $ 0.4