v3.26.1
Long-term debt - Senior Notes (Details) - 9.50% Senior Secured Notes due 2029
€ in Thousands, $ in Millions
Mar. 31, 2026
EUR (€)
Mar. 31, 2026
USD ($)
Dec. 31, 2025
USD ($)
Long-term debt      
Debt instrument interest rate 9.50% 9.50% 9.50%
Kronos International, Inc      
Long-term debt      
Debt instrument interest rate 9.50% 9.50% 9.50%
Debt instrument principal amount | € € 426,174    
Unamortized premium   $ 8.4 $ 9.0
Unamortized debt issuance costs   $ 6.2 $ 6.9