Stock-Based Compensation Plans - Summary of Awards Made under Plans (Detail) - $ / shares |
9 Months Ended | |
|---|---|---|
Sep. 30, 2016 |
Sep. 30, 2015 |
|
| Stock Options | ||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
| Shares - Stock Options | 1,333,210 | 1,638,540 |
| Grant date fair value per share of unvested option awards as calculated from above | $ 6.24 | $ 10.02 |
| Restricted Stock Units | ||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
| Shares - Other than Stock Options | 1,117,495 | 800,500 |
| Fair Value - Other than Stock Options | $ 14.27 | $ 24.64 |
| Total Shareholder Return (TSR) Performance Awards | ||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
| Shares - Other than Stock Options | 308,130 | 273,560 |
| Fair Value - Other than Stock Options | $ 10.02 | $ 24.95 |