Components of Coal Workers' Pneumoconiosis (CWP) and Workers' Compensation Net Periodic Benefit Costs (Details) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| CWP | ||||
| Defined Contribution Plan Disclosure [Line Items] | ||||
| Service Cost | $ 1,691 | $ 1,990 | $ 3,381 | $ 3,806 |
| Interest Cost | 3,381 | 3,670 | 6,763 | 7,089 |
| Recognized Net Actuarial Loss (Gain) | 318 | 43 | 635 | 85 |
| State Administrative Fees and Insurance Bond Premiums | 0 | 0 | 0 | 0 |
| Net Periodic Benefit Cost | 5,390 | 5,703 | 10,779 | 10,980 |
| Workers' Compensation | ||||
| Defined Contribution Plan Disclosure [Line Items] | ||||
| Service Cost | 3,195 | 1,728 | 6,390 | 3,456 |
| Interest Cost | 501 | 555 | 1,002 | 1,110 |
| Recognized Net Actuarial Loss (Gain) | (356) | (460) | (712) | (920) |
| State Administrative Fees and Insurance Bond Premiums | 795 | 740 | 1,561 | 1,130 |
| Net Periodic Benefit Cost | 4,135 | 2,563 | 8,241 | 4,776 |
| Insured Workers’ Compensation Fees and Assessments | 518 | 1,634 | 1,037 | 2,980 |
| Total Workers’ Compensation Expense | $ 4,653 | $ 4,197 | $ 9,278 | $ 7,756 |
| X | ||||||||||
- Definition Defined Benefit Plan, Workers Compensation Expense No definition available.
|
| X | ||||||||||
- Definition Defined Benefit Plan, Workers Compensation Expense Insured Portion No definition available.
|
| X | ||||||||||
- Definition State Administrative Fees and Insurance Bond Premiums No definition available.
|
| X | ||||||||||
- Definition Amount of gain (loss) recognized in net periodic benefit (cost) credit of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
|
| X | ||||||||||
- Definition Amount of cost recognized for passage of time related to defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
|
| X | ||||||||||
- Definition Amount of net periodic benefit cost (credit) for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|