Stock-Based Compensation - Additional Information (Detail) - shares |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2017 |
Jun. 30, 2016 |
Jun. 30, 2017 |
Jun. 30, 2016 |
|
| Time-based Restricted Units [Member] | ||||
| Stock Based Compensation [Line Items] | ||||
| Restricted units awarded to managers (shares) | 417,266 | 14,288 | 447,477 | 14,288,000 |
| Performance-based Restricted Units [Member] | ||||
| Stock Based Compensation [Line Items] | ||||
| Restricted units awarded to managers (shares) | 365,539 | 5,102 | 365,539,000 | 308,163 |