v3.26.1
Workers' Compensation and Pneumoconiosis (Tables)
6 Months Ended
Jun. 30, 2026
Defined Benefit Plan Disclosure [Line Items]  
Reconciliation of changes in workers' compensation liability

The changes in the workers’ compensation liability, including current and long-term liability balances, for each of the periods presented were as follows:

  ​ ​ ​

Three Months Ended

Six Months Ended

 

June 30, 

June 30, 

2026

  ​ ​ ​

2025

  ​ ​ ​

2026

  ​ ​ ​

2025

(in thousands)

Beginning balance

$

49,320

$

48,511

$

49,378

$

47,870

Changes in accruals

 

3,258

 

3,419

 

6,602

 

6,795

Payments

 

(3,926)

 

(3,762)

 

(7,866)

 

(7,064)

Interest accretion

 

539

 

570

 

1,077

 

1,137

Valuation loss (gain) (1)

 

(614)

496

 

(614)

496

Ending balance

$

48,577

$

49,234

$

48,577

$

49,234

(1)Our estimate of the liability for the present value of current workers′ compensation benefits is based on our actuarial calculations.  Our actuarial calculations are based on a blend of actuarial projection methods and numerous assumptions including claims development patterns, mortality, medical costs and interest rates.  The valuation gain in 2026 is due to an increase in the discount rate from 4.78% on December 31, 2025 to 5.10% on June 30, 2026. The valuation loss in 2025 is due to a decrease in the discount rate from 5.17% on December 31, 2024 to 4.92% on June 30, 2025.  
Pneumoconiosis benefits  
Defined Benefit Plan Disclosure [Line Items]  
Components of net periodic benefit cost

  ​ ​ ​

Three Months Ended

Six Months Ended

June 30, 

June 30, 

2026

  ​ ​ ​

2025

  ​ ​ ​

2026

  ​ ​ ​

2025

 

(in thousands)

Service cost

$

723

$

889

$

1,443

$

1,748

 

Interest cost (1)

 

1,399

 

1,686

 

2,797

 

3,352

Amortization of net actuarial loss (1)

 

116

 

232

 

232

 

464

Other adjustments (1) (2)

(6,450)

Net periodic benefit cost

$

2,238

$

2,807

$

(1,978)

$

5,564

(1)Interest cost, amortization of net actuarial loss and other adjustments are included in the Other income line item within our condensed consolidated statements of income.
(2)This line item includes an immaterial adjustment related to the correction of actuarial assumptions for terminated employees in the prior period.