XML 88 R74.htm IDEA: XBRL DOCUMENT v3.20.4
Treasury Stock - Additional Information (Detail) - USD ($)
 12 Months Ended
Aug. 11, 2020
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Equity, Class of Treasury Stock [Line Items]        
Treasury stock, shares repurchased value   $ 123,224,000 $ 72,719,000 $ 110,977,000
Treasury stock, shares   8,684,000 7,807,000  
Treasury stock, cost   $ 782,104,000 $ 658,880,000  
Class A        
Equity, Class of Treasury Stock [Line Items]        
Treasury stock, shares repurchased   0 0 0
Treasury stock, shares repurchased value   $ 0 $ 0 $ 0
Class A | Share Repurchase Program        
Equity, Class of Treasury Stock [Line Items]        
Shares repurchased program expiration date   Apr. 29, 2023    
Stock authorized to repurchase by board of directors   $ 800,000,000.0    
Treasury stock, shares repurchased   444,769 521,843 880,667
Shares repurchased, average price per share   $ 139.12 $ 139.35 $ 126.02
Treasury stock, shares repurchased value   $ 61,900,000 $ 72,700,000 $ 111,000,000.0
Treasury stock, shares   5,674,226    
Shares repurchased, average price per share   $ 104.13    
Treasury stock, cost   $ 590,900,000    
Stock remaining available for repurchase   $ 209,100,000    
Class A | Tender Offer        
Equity, Class of Treasury Stock [Line Items]        
Treasury stock, shares repurchased   432,313    
Shares repurchased, average price per share   $ 140.00    
Treasury stock, shares repurchased value   $ 61,300,000    
Tender offer, purchase price maximum $ 140.00      
Tender offer, purchase price minimum $ 122.00      
Tender offer expiration date Sep. 10, 2020      
Expenses and fees related to tender offer   $ 800,000    
Class A | Tender Offer | Maximum        
Equity, Class of Treasury Stock [Line Items]        
Tender offer program, authorized amount $ 250,000,000.0