Stanwell Liabilities (Schedule of Contract Obligations) (Details) $ in Thousands, $ in Millions |
Mar. 31, 2026
AUD ($)
|
Mar. 31, 2026
USD ($)
|
Dec. 31, 2025
USD ($)
|
Aug. 14, 2018
AUD ($)
|
Aug. 14, 2018
USD ($)
|
|---|---|---|---|---|---|
| Contract Obligations [Line Items] | |||||
| Contract obligations, Non-current | $ 18,782 | $ 21,173 | |||
| Deferred consideration liability | 365,493 | 346,768 | |||
| Stanwell liabilities | 562,961 | 501,795 | |||
| Stanwell Reserve Area Deferred Consideration [Member] | |||||
| Contract Obligations [Line Items] | |||||
| Deferred consideration liability | $ 210.0 | $ 155,200 | |||
| Stanwell Prepaid Coal Supply Liability [Member] | |||||
| Contract Obligations [Line Items] | |||||
| Contract obligations | $ 250.7 | 171,600 | 155,027 | ||
| Stanwell Prepayment And Deferred Payment [Member] | |||||
| Contract Obligations [Line Items] | |||||
| Contract obligations, Non-current | $ 25,830 | $ 0 |