Awards Granted to Company Employees and Non-employee Directors Under the 2007 Equity Incentive Compensation Plan (Detail) (USD $)
6 Months Ended 0 Months Ended
Mar. 31, 2015
Mar. 19, 2015
Jan. 28, 2015
Non-qualified stock options      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Granted 1,408,388    
Weighted-Average Grant Date Fair Value $ 12.00    
Weighted-Average Exercise Price $ 62.59    
Restricted stock awards (RSAs)      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Granted 1,855,076    
Weighted-Average Grant Date Fair Value $ 62.78    
Restricted stock units (RSUs)      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Granted 733,340    
Weighted-Average Grant Date Fair Value $ 62.56    
Performance-bases shares      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Granted 785,884 [1]    
Weighted-Average Grant Date Fair Value $ 69.78 [1]    
Class A common stock      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock split, conversion ratio   4  
Employee Stock Purchase Program [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Discount from market price on purchase date (percent)     15.00%
Shares reserved for issuance (shares)     20,000,000
[1] Represents the maximum number of performance-based shares which could be earned.