Stock-Based Compensation Plans - Narrative (Detail) |
3 Months Ended |
|---|---|
|
Mar. 31, 2018
$ / shares
| |
| Stock Options | |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |
| Grant date fair value (in USD per share) | $ 17.37 |
| Performance Unit Awards | |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |
| Granted (in USD per share) | $ 0.83 |