Income Taxes - Earliest Tax Years Subject to Examination by Major Jurisdiction (Detail) |
12 Months Ended |
|---|---|
Dec. 31, 2020 | |
| U.S. Federal [Member] | |
| Income Tax Examination [Line Items] | |
| Open tax years by major tax jurisdiction | 2011 |
| New York State and City [Member] | |
| Income Tax Examination [Line Items] | |
| Open tax years by major tax jurisdiction | 2015 |
| United Kingdom [Member] | Foreign Tax Authority [Member] | |
| Income Tax Examination [Line Items] | |
| Open tax years by major tax jurisdiction | 2017 |
| Japan [Member] | Foreign Tax Authority [Member] | |
| Income Tax Examination [Line Items] | |
| Open tax years by major tax jurisdiction | 2015 |
| Hong Kong [Member] | Foreign Tax Authority [Member] | |
| Income Tax Examination [Line Items] | |
| Open tax years by major tax jurisdiction | 2014 |