| 
            Mar 31                          
            2016                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $260,112,121              
              $93.98 p/Share              
                   
         |    
        
           
              2,767,739
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Mar 30                          
            2016                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $375,079,987              
              $93.77 p/Share              
                   
         |    
        
           
              4,000,000
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Mar 29                          
            2016                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $182,739,975              
              $92.97 p/Share              
                   
         |    
        
           
              1,965,580
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Mar 28                          
            2016                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $9,253,000              
              $92.53 p/Share              
                   
         |    
        
           
              100,000
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Mar 24                          
            2016                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $76,025,460              
              $92.51 p/Share              
                   
         |    
        
           
              821,808
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Mar 23                          
            2016                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $37,039,999              
              $92.6 p/Share              
                   
         |    
        
           
              400,000
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Mar 22                          
            2016                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $96,623,248              
              $92.9 p/Share              
                   
         |    
        
           
              1,040,078
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Mar 21                          
            2016                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $62,350,627              
              $92.71 p/Share              
                   
         |    
        
           
              672,534
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Jan 29                          
            2016                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $16,466,850              
              $89.01 p/Share              
                   
         |    
        
           
              185,000
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Jan 25                          
            2016                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $445,000              
              $89.0 p/Share              
                   
         |    
        
           
              5,000
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Jan 22                          
            2016                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $143,903,235              
              $89.27 p/Share              
                   
         |    
        
           
              1,612,000
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Jan 21                          
            2016                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $38,958,599              
              $89.56 p/Share              
                   
         |    
        
           
              435,000
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Jul 16                          
            2015                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $41,224,998              
              $82.45 p/Share              
                   
         |    
        
           
              500,000
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Jul 15                          
            2015                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $41,029,999              
              $82.06 p/Share              
                   
         |    
        
           
              500,000
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Jul 14                          
            2015                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $56,902,230              
              $82.11 p/Share              
                   
         |    
        
           
              693,000
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Jun 30                          
            2015                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $3,036,960              
              $82.08 p/Share              
                   
         |    
        
           
              37,000
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Jun 29                          
            2015                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $9,022,200              
              $82.02 p/Share              
                   
         |    
        
           
              110,000
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Jun 26                          
            2015                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $13,368,000              
              $83.55 p/Share              
                   
         |    
        
           
              160,000
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Dec 24                          
            2014                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $22,416,000              
              $74.72 p/Share              
                   
         |    
        
           
              300,000
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Dec 23                          
            2014                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $29,867,999              
              $74.67 p/Share              
                   
         |    
        
           
              400,000
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Dec 22                          
            2014                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $80,917,100              
              $74.57 p/Share              
                   
         |    
        
           
              1,085,116
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Dec 19                          
            2014                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $112,080,002              
              $74.72 p/Share              
                   
         |    
        
           
              1,500,000
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Dec 18                          
            2014                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $187,549,992              
              $75.02 p/Share              
                   
         |    
        
           
              2,500,000
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Dec 17                          
            2014                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $70,015,047              
              $74.09 p/Share              
                   
         |    
        
           
              945,000
              
         | 
        
          
            
          
         |        
      
 
      
      
        | 
            Dec 15                          
            2014                          
         |  
        
          
            
              SELL
             
            
                Open market or private sale
             
                            
         | 
        
           
              $84,410,997              
              $74.7 p/Share              
                   
         |    
        
           
              1,130,000
              
         | 
        
          
            
          
         |