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Workers' Compensation And Pneumoconiosis - Benefit cost (Details) - Pneumoconiosis benefits - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Service cost | $ 864 | $ 864 | $ 2,612 | $ 2,583
Interest cost | $ 1,677 | $ 1,558 | $ 5,029 | $ 4,674
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Interest Cost, Statement of Income or Comprehensive Income [Extensible Enumeration] | Other Nonoperating Income (Expense) | Other Nonoperating Income (Expense) | Other Nonoperating Income (Expense) | Other Nonoperating Income (Expense)
Net amortization | $ 232 | $ 839 | $ 696 | $ 2,517
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Amortization of Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] | Other Nonoperating Income (Expense) | Other Nonoperating Income (Expense) | Other Nonoperating Income (Expense) | Other Nonoperating Income (Expense)
Net periodic benefit cost | $ 2,773 | $ 3,261 | $ 8,337 | $ 9,774

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