Shareholders' Equity - Dividends Declared on Common Stock (Detail) - $ / shares |
3 Months Ended | 6 Months Ended | |||
|---|---|---|---|---|---|
Apr. 13, 2021 |
Jun. 30, 2021 |
Jun. 30, 2020 |
Jun. 30, 2021 |
Jun. 30, 2020 |
|
| Equity [Abstract] | |||||
| Dividends declared per common share | $ 1.25 | $ 1.25 | $ 1.25 | $ 2.50 | $ 2.50 |