v3.26.1
Commitments and contingencies - Changes in Accrued Environmental Remediation and Related Costs (Details) - USD ($)
$ in Thousands
6 Months Ended
Jun. 30, 2026
Dec. 31, 2025
Commitments and contingencies.    
Balance at the beginning of the period $ 13,040  
Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration] Current liability, Noncurrent liability Current liability, Noncurrent liability
Additions charged to expense, net $ 561  
Payments, net (872)  
Balance at the end of the period $ 12,729  
Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration] Current liability, Noncurrent liability Current liability, Noncurrent liability
Amounts recognized in the balance sheet:    
Current liability $ 1,951 $ 2,071
Noncurrent liability $ 10,778 $ 10,969