v3.26.3
Earnings Per Common Share - Net Income, Weighted Average Common Shares Used in Calculating Basic Earnings Per Common Share and Diluted EPS (Details) - USD ($)
$ / shares in Units, $ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Numerator        
Net income $ 275.2 $ 265.6 $ 847.9 $ 647.5
Less: Earnings allocated to participating securities, basic (2.2) (2.3) (6.8) (5.8)
Less: Earnings allocated to participating securities, diluted (2.2) (2.3) (6.8) (5.8)
Net income used in diluted per common share calculations, basic 273.0 263.3 841.1 641.7
Net income used in basic per common share calculations, diluted $ 273.0 $ 263.3 $ 841.1 $ 641.7
Denominator        
Weighted average common shares outstanding used in basic per common share calculations (in shares) 49,283,903 50,395,469 49,500,842 50,621,953
Incremental common shares from:        
Weighted average common shares outstanding used in diluted per common share calculations (in shares) 49,716,580 50,884,296 49,996,112 51,147,799
Basic (in dollars per share) $ 5.54 $ 5.22 $ 16.99 $ 12.67
Diluted (in dollars per share) $ 5.49 $ 5.17 $ 16.82 $ 12.55
PSUs        
Incremental common shares from:        
Incremental common shares (in shares) 431,952 488,827 495,270 525,846
ESPP        
Incremental common shares from:        
Incremental common shares (in shares) 725 0 0 0