Earnings Per Common Share - Additional Information (Detail) - $ / shares shares in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Earnings per common share | |||
| Reduction per common share due to impact of applying the amended principles to basic earnings per common share | $ 0.07 | $ 0.07 | $ 0.05 |
| Number of antidilutive RSUs | 0.1 | 0.1 | |
| Maximum [Member] | |||
| Earnings per common share | |||
| Number of antidilutive RSUs | 0.1 | ||