XML 95 R77.htm IDEA: XBRL DOCUMENT v3.3.1.900
Stock-Based Incentive Plans - Movement in Outstanding Shares of Restricted Class A Common Stock and Weighted-Average Grant Date Fair Value Per Share (Detail) - Restricted Class A Common Stock [Member] - $ / shares
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Restricted Class A Common Stock, Beginning Balance 919,719 700,000
Restricted Class A Common Stock, Granted 679,958 490,381
Restricted Class A Common Stock, Vested (456,626) (270,662)
Restricted Class A Common Stock, Forfeited (28,143)  
Restricted Class A Common Stock, Ending Balance 1,114,908 919,719
Weighted-Average Grant Date Fair Value Per Share, Beginning Balance $ 26.86 $ 25.69
Weighted-Average Grant Date Fair Value Per Share, Granted 28.25 27.82
Weighted-Average Grant Date Fair Value Per Share, Vested 26.94 25.57
Weighted-Average Grant Date Fair Value Per Share, Forfeited 28.28  
Weighted-Average Grant Date Fair Value Per Share, Ending Balance $ 27.64 $ 26.86