v3.26.1
Organization and basis of presentation - Additional Information (Detail)
Mar. 31, 2026
NL Industries | CompX International Inc  
Organization and basis of presentation:  
Percentage of ownership held by parent company 87.00%
Valhi Inc | NL Industries  
Organization and basis of presentation:  
Percentage of ownership held by parent company 83.00%
Contran Corporation | Valhi Inc  
Organization and basis of presentation:  
Percentage of ownership held by parent company 91.00%