v3.25.4
Goodwill and other intangible assets - Customer Relationship Intangible Assets (Details) - Customer Relationships - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Finite-Lived Intangible Assets [Line Items]    
Cost $ 169,085 $ 169,085
Accumulated amortization (107,673) (103,093)
Net carrying amount 61,412 65,992
Bermuda    
Finite-Lived Intangible Assets [Line Items]    
Cost 29,785 29,785
Accumulated amortization (22,156) (20,727)
Net carrying amount 7,629 9,058
Cayman    
Finite-Lived Intangible Assets [Line Items]    
Cost 16,517 16,517
Accumulated amortization (11,068) (9,967)
Net carrying amount 5,449 6,550
Channel Islands and the UK    
Finite-Lived Intangible Assets [Line Items]    
Cost 97,860 97,860
Accumulated amortization (69,113) (67,760)
Net carrying amount 28,747 30,100
Other    
Finite-Lived Intangible Assets [Line Items]    
Cost 24,923 24,923
Accumulated amortization (5,336) (4,639)
Net carrying amount $ 19,587 $ 20,284