v3.26.1
Accounting Policies - Narrative (Details)
$ in Millions
3 Months Ended 6 Months Ended
Mar. 31, 2026
USD ($)
Mar. 31, 2026
USD ($)
Jun. 30, 2026
USD ($)
Dec. 31, 2025
USD ($)
Dec. 31, 2024
Sep. 30, 2024
Apr. 30, 2024
Mar. 31, 2024
Oct. 31, 2021
Mar. 31, 2021
Inventories                    
Materials and supplies inventory     $ 132.4 $ 144.9            
Hydrocarbons inventory     7.5 $ 27.7            
Facility                    
Cash, Cash Equivalents and Restricted Cash                    
Debt cover ratio 2.50 2.50         2.50      
Restricted cash required   $ 23.5                
Debt service reserve account $ 23.5   $ 23.5              
Facility Interest or Senior Notes                    
Cash, Cash Equivalents and Restricted Cash                    
Period for contractual future interest payments     6 months              
7.750% Senior Notes | Senior Notes                    
Cash, Cash Equivalents and Restricted Cash                    
Interest rate (as a percent)                 7.75%  
7.500% Senior Notes | Senior Notes                    
Cash, Cash Equivalents and Restricted Cash                    
Interest rate (as a percent)                   7.50%
8.750% Senior Notes | Senior Notes                    
Cash, Cash Equivalents and Restricted Cash                    
Interest rate (as a percent)           8.75%        
3.125% Convertible Senior Notes | Senior Notes                    
Cash, Cash Equivalents and Restricted Cash                    
Interest rate (as a percent)     3.125% 3.125% 3.125%     3.125%