Stock-Based Compensation - Restricted Stock and RSU Activity (Parenthetical) (Detail) shares in Millions |
Dec. 31, 2015
shares
|
|---|---|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |
| Share-based compensation awards expected to vest | 2.8 |
| Awards vested, not converted | 0.2 |
| Market Performance-based RSUs [Member] | |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |
| Share-based compensation awards expected to vest | 1.3 |