v3.25.2
Note 11 - Compensation Plans - Summary of Stock Activity (Details) - USD ($)
$ / shares in Units, $ in Millions
 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Dec. 31, 2024
Outstanding beginning balance, options (in shares) 1,910,333    
Outstanding beginning balance, options, weighted average exercise price (in dollars per share) $ 161.16    
Outstanding, options, aggregate intrinsic value $ 232.7   $ 218.3
Granted, options (in shares) 213,569    
Weighted average grant price (in dollars per share) $ 273.92 $ 236.76  
Dividend reinvestment, options (in shares) 0    
Exercised or lapsed, options (in shares) (349,903)    
Exercised or lapsed, options, weighted average exercise price (in dollars per share) $ 136.01    
Exercised or lapsed, options, aggregate intrinsic value $ 56.8    
Canceled, expired or forfeited, option (in shares) (13,113)    
Canceled, expired or forfeited, options, weighted average exercise price (in dollars per share) $ 222.78    
Outstanding, option (in shares) 1,760,886    
Outstanding beginning balance, options, weighted average exercise price (in dollars per share) $ 179.37    
Exercisable, options (in shares) 1,237,430   1,345,181
Exercisable, options, weighted average exercise price (in dollars per share) $ 155.3   $ 142.14
Exercisable, options, aggregate intrinsic value $ 193.3   $ 179.3
Nonvested, options (in shares) 523,456    
Expected to vest, options (in shares) 435,958    
Restricted Stock [Member]      
Outstanding beginning balance, number of shares (in shares) 307,541    
Outstanding beginning balance, weighted average exercise price (in dollars per share) $ 210.62    
Granted, number of shares (in shares) 140,280    
Granted, weighted average exercise price (in dollars per share) $ 276.09    
Dividend reinvestment, number of shares (in shares) 0    
Exercised or lapsed, number of shares (in shares) (108,983)    
Exercised or lapsed, weighted average exercise price (in dollars per share) $ 207.63    
Canceled, expired or forfeited, number of shares (in shares) (8,954)    
Canceled, expired or forfeited, weighted average exercise price (in dollars per share) $ 233.22    
Outstanding ending balance, number of shares (in shares) 329,884    
Outstanding ending balance, weighted average exercise price (in dollars per share) $ 239.28    
Nonvested, number of shares (in shares) 329,884   307,541
Expected, number of shares (in shares) 290,588    
Performance Shares [Member]      
Outstanding beginning balance, number of shares (in shares) 180,456    
Outstanding beginning balance, weighted average exercise price (in dollars per share) $ 205.1    
Granted, number of shares (in shares) 46,225    
Granted, weighted average exercise price (in dollars per share) $ 309.25    
Dividend reinvestment, number of shares (in shares) 481    
Exercised or lapsed, number of shares (in shares) (84,592)    
Exercised or lapsed, weighted average exercise price (in dollars per share) $ 167.9    
Canceled, expired or forfeited, number of shares (in shares) (1,710)    
Canceled, expired or forfeited, weighted average exercise price (in dollars per share) $ 212.88    
Outstanding ending balance, number of shares (in shares) 140,859    
Outstanding ending balance, weighted average exercise price (in dollars per share) $ 262.78    
Nonvested, number of shares (in shares) 140,859   180,456
Expected, number of shares (in shares) [1] 242,386    
[1] Includes estimated performance achievement