Fair Value Measurements and Derivative Instruments - Schedule of Outstanding Fuel Swap Agreements (Details) - Fuel Swap Agreements - metricTon |
Sep. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| 2026 | ||
| Derivative Instruments | ||
| Fuel swap agreements (metric tons) | 269,700 | 1,065,500 |
| Percentage of projected requirements | 59.00% | 60.00% |
| 2027 | ||
| Derivative Instruments | ||
| Fuel swap agreements (metric tons) | 960,048 | 819,048 |
| Percentage of projected requirements | 53.00% | 47.00% |
| 2028 | ||
| Derivative Instruments | ||
| Fuel swap agreements (metric tons) | 545,599 | 465,699 |
| Percentage of projected requirements | 29.00% | 26.00% |
| 2029 | ||
| Derivative Instruments | ||
| Fuel swap agreements (metric tons) | 281,400 | 0 |
| Percentage of projected requirements | 14.00% | 0.00% |