Summary of Significant Accounting Policies - Property and Equipment (Detail) |
12 Months Ended |
|---|---|
Dec. 31, 2019 | |
| Building | |
| Property and Equipment [Line Items] | |
| Property and equipment, useful life (in years) | 39 years |
| Minimum | Computer equipment and software | |
| Property and Equipment [Line Items] | |
| Property and equipment, useful life (in years) | 3 years |
| Minimum | Furniture and fixtures | |
| Property and Equipment [Line Items] | |
| Property and equipment, useful life (in years) | 3 years |
| Maximum | Computer equipment and software | |
| Property and Equipment [Line Items] | |
| Property and equipment, useful life (in years) | 5 years |
| Maximum | Furniture and fixtures | |
| Property and Equipment [Line Items] | |
| Property and equipment, useful life (in years) | 7 years |