v3.26.3
Fair Value Measurements (Schedule Of Carrying Values And Estimated Fair Values Of Debt Instruments) (Details) - USD ($)
$ in Millions
Sep. 30, 2026
Dec. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
LONG-TERM NOTES RECEIVABLE FROM ARO $ 363.4 $ 345.0
ARO    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
LONG-TERM NOTES RECEIVABLE FROM ARO 363.4 345.0
Reported Value Measurement [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
LONG-TERM NOTES RECEIVABLE FROM ARO 363.4 345.0
Reported Value Measurement [Member] | Eight Point Three Seven Five Percent Senior Second Lien Notes | Senior Notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-Term Debt 1,088.5 1,086.0
Estimate of Fair Value Measurement [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
LONG-TERM NOTES RECEIVABLE FROM ARO 411.5 403.8
Estimate of Fair Value Measurement [Member] | Eight Point Three Seven Five Percent Senior Second Lien Notes | Senior Notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-Term Debt $ 1,125.2 $ 1,144.9