Commitments and contingencies - Additional Information (Details) $ in Thousands	Mar. 31, 2026 USD ($) site	Dec. 31, 2025 USD ($)
Commitments and contingencies
Accrual for reasonably estimable environmental remediation and related matters	$ 12,969	$ 13,040
Environmental Remediation Sites NL Named As PRP Or Defendant
Commitments and contingencies
Accrual for reasonably estimable environmental remediation and related matters	$ 13,000
Number of sites associated with remediation and related costs | site	27
Number of sites currently not able to reasonably estimate a range of costs | site	5
Maximum | Environmental Remediation Sites NL Named As PRP Or Defendant
Commitments and contingencies
Upper end range, estimate costs for remediation and related matters	$ 38,000