v3.26.1
Reserve for Known and Incurred but Not Reported Claims (Summary of Loss Reserves) (Detail) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Jun. 30, 2025
Dec. 31, 2024
Liability for Claims and Claims Adjustment Expense [Line Items]        
Known title claims, amount $ 75.0 $ 54.6    
Incurred but not reported claims, amount 1,053.9 1,095.9    
Non-title claims, amount 22.7 19.1    
Total loss reserves, amount $ 1,151.6 $ 1,169.6 $ 1,189.3 $ 1,193.4
Known title claims, percent 6.50% 4.70%    
Incurred but not reported claims, percent 91.50% 93.70%    
Total title claims, percent 98.00% 98.40%    
Non-title claims, percent 2.00% 1.60%    
Total loss reserves, percent 100.00% 100.00%    
Title Claims        
Liability for Claims and Claims Adjustment Expense [Line Items]        
Total loss reserves, amount $ 1,128.9 $ 1,150.5