v3.26.1
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 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Numerator        
Net income $ 298.6 $ 235.3 $ 572.7 $ 381.9
Less: Earnings allocated to participating securities, basic (2.3) (2.1) (4.6) (3.5)
Less: Earnings allocated to participating securities, diluted (2.3) (2.1) (4.6) (3.5)
Net income used in diluted per common share calculations, basic 296.3 233.2 568.1 378.4
Net income used in basic per common share calculations, diluted $ 296.3 $ 233.2 $ 568.1 $ 378.4
Denominator        
Weighted average common shares outstanding used in basic per common share calculations (in shares) 49,520,710 50,675,804 49,611,108 50,737,072
Incremental common shares from:        
Weighted average common shares outstanding used in diluted per common share calculations (in shares) 49,831,416 51,112,351 50,082,767 51,248,193
Basic (in dollars per share) $ 5.98 $ 4.60 $ 11.45 $ 7.46
Diluted (in dollars per share) $ 5.95 $ 4.56 $ 11.34 $ 7.38
PSUs        
Incremental common shares from:        
Incremental common shares (in shares) 271,103 393,648 432,056 468,222
ESPP        
Incremental common shares from:        
Incremental common shares (in shares) 39,603 42,899 39,603 42,899