Stock-Based Compensation - Stock Option Activity (Detail) - Performance-Based Stock Options [Member] |
12 Months Ended |
|---|---|
|
Dec. 31, 2020
$ / shares
shares
| |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |
| Outstanding, Shares Under Option, Beginning of Period | shares | 1,941,145 |
| Outstanding, Shares Under Option, Forfeited | shares | (25,353) |
| Outstanding, Shares Under Option, End of Period | shares | 1,915,792 |
| Weighted Average Exercise Price, Beginning of Period | $ / shares | $ 513.50 |
| Weighted Average Exercise Price, Forfeited | $ / shares | 513.50 |
| Weighted Average Exercise Price, End of Period | $ / shares | $ 513.50 |