Earnings Per Share - Additional Information (Detail) - shares shares in Thousands |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2016 |
Sep. 30, 2015 |
Sep. 30, 2016 |
Sep. 30, 2015 |
|
| Earnings Per Share [Abstract] | ||||
| Weighted average employee stock options excluded from the determination of diluted net income per common and common equivalent share (in shares) | 129 | 148 | 148 | 112 |