Quarterly report pursuant to Section 13 or 15(d)

Equity-Based Compensation - Restricted Stock and RSUs to be Settled in Common Stock (Detail)

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Equity-Based Compensation - Restricted Stock and RSUs to be Settled in Common Stock (Detail) - USD ($)
$ / shares in Units, $ in Thousands, shares in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Non-cash stock compensation expense $ 11,557 $ 9,503 $ 23,423 $ 23,222
Restricted Stock Units to be Settled in Common Stock        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Granted, shares (in shares) 0.1 0.1 1.2 1.8
Granted, weighted average grant date fair value, per share (in usd per share) $ 33.32 $ 23.59 $ 37.76 $ 22.11
Unrecognized compensation cost, related to unvested RSUs to be settled in common stock, total $ 49,200   $ 49,200  
Expected weighted average period to recognize compensation cost on RSUs to be settled in common stock (in years)     1 year 10 months 21 days  
Restricted Stock and Restricted Stock Units to be Settled in Common Stock        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Awards vested (in shares) 0.1 0.1 1.4 1.3
Fair value of restricted stock, vested $ 3,800 $ 1,100 $ 54,300 $ 26,400
Non-cash stock compensation expense $ 10,100 $ 8,500 $ 21,300 $ 21,700
Restricted Stock and Restricted Stock Units to be Settled in Common Stock | Minimum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting period for RSUs to be settled in stock     2 years  
Restricted Stock and Restricted Stock Units to be Settled in Common Stock | Maximum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting period for RSUs to be settled in stock     3 years