Equity-Based Compensation - Additional Information (Detail) - USD ($) |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2015 |
Sep. 30, 2014 |
Sep. 30, 2015 |
Sep. 30, 2014 |
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||
| Restricted stock expense | $ 5,300,000 | $ 2,300,000 | $ 11,100,000 | $ 7,000,000 |
| Stock option expense | $ 0 | $ 0 | $ 0 | $ 0 |
| Restricted Stock Awards | ||||
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||
| Number of restricted stock awards granted in the period | 222,601 | 34,143 | 576,882 | 390,070 |