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Stock-Based Compensation - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended 276 Months Ended 336 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2016
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Percentage of incentive compensation to acquire shares, maximum 50.00%            
Percentage of discount rate to market value on the incentive compensation 20.00%            
Common stock price $ 498.91       $ 498.91 $ 498.91  
Aggregate intrinsic values of options exercised $ 2.6 $ 1.3 $ 2.3        
Aggregate intrinsic values for options exercisable $ 2.2       $ 2.2 $ 2.2  
Awards available for grant 400,000       400,000 400,000  
Additional shares issuance under the plan       800,000      
Total tax benefits related to stock-based compensation expense $ 8.6 $ 7.6 $ 7.9        
Options granted in 2015 and 2014              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Employee stock options expiration date 10 years            
Incentive Compensation Stock Awards              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Weighted-average grant-date fair value of stock awards, granted $ 362.08 $ 369.05 $ 325.3        
Aggregate intrinsic values for stock awards $ 3.6       $ 3.6 $ 3.6  
Common stock price $ 498.91       $ 498.91 $ 498.91  
Aggregate intrinsic values of stock awards, distributed $ 3.9 $ 3.1 $ 4.9        
Awards granted 4,012            
Restricted Stock - Service Based Awards              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Weighted-average grant-date fair value of stock awards, granted $ 369.18 $ 362.77 $ 342.11        
Awards granted 60,982            
Restricted Stock - Performance Based Awards              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Weighted-average grant-date fair value of stock awards, granted $ 392.73 $ 406.99 $ 352.52        
Awards granted 33,103            
Restricted Stock Awards              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Aggregate intrinsic values for stock awards $ 154.1       $ 154.1 $ 154.1  
Aggregate intrinsic values of stock awards, distributed $ 47.6 $ 64.5 $ 41.1        
Shareholder Value Achievement Plan (1996)              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Common stock reserved for future issuance             300,000
Common stock issued under the plan           42,025  
Awards granted         0    
Directors' Awards              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Common stock reserved for future issuance 300,000       300,000 300,000  
Common stock issued under the plan 1,333 1,767 1,686