v3.26.1
Financial risk management - Changes in liabilities (Details) - USD ($)
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Financial risk management    
Beginning of period $ 208,613,000 $ 345,020,000
Liabilities Arising From Financing Activities Excluding Tolling Agreement Lease Liability   208,613,000
Changes from financing cash flows 21,208,000 (155,123,000)
Effect of changes in foreign exchange rates 22,772,000 (10,331,000)
Interest expense 13,943,000 15,992,000
Other changes 2,616,000 13,055,000
End of period 269,152,000 208,613,000
Dividends paid (10,451,000) (9,758,000)
Other amounts paid due to net financing activities (17,744,000) (20,385,000)
Payments to acquire own shares (4,691,000) (2,428,000)
Net cash (used) in financing activities 3,464,000 (175,508,000)
Bank borrowings.    
Financial risk management    
Beginning of period 57,162,000 46,548,000
Changes from financing cash flows 71,108,000 9,529,000
Effect of changes in foreign exchange rates 6,839,000 (2,389,000)
Interest expense 5,000,000 3,887,000
Other changes (97,000) (413,000)
End of period 140,012,000 57,162,000
Obligations under leases    
Financial risk management    
Beginning of period 69,452,000 66,250,000
Changes from financing cash flows (16,186,000) (16,201,000)
Effect of changes in foreign exchange rates 7,849,000 (3,794,000)
Interest expense 5,906,000 5,935,000
Other changes 2,662,000 17,262,000
End of period 69,683,000 69,452,000
Debt instruments    
Financial risk management    
Beginning of period 10,135,000 154,780,000
Changes from financing cash flows 13,117,000 (144,993,000)
Effect of changes in foreign exchange rates 1,726,000 (114,000)
Interest expense 1,036,000 1,799,000
Other changes   (1,337,000)
End of period 26,014,000 10,135,000
Financial loans from government agencies    
Financial risk management    
Beginning of period 71,864,000 77,442,000
Changes from financing cash flows (46,831,000) (3,458,000)
Effect of changes in foreign exchange rates 6,358,000 (4,034,000)
Interest expense 2,001,000 4,371,000
Other changes 51,000 (2,457,000)
End of period $ 33,443,000 $ 71,864,000