Stockholders' Equity - Summary of Shares Issued and Held in Treasury or Outstanding (Detail) - shares |
Mar. 31, 2021 |
Dec. 31, 2020 |
---|---|---|
Class A Common Stock [Member] | ||
Class of Stock [Line Items] | ||
Common stock - issued | 17,301,199 | 17,224,830 |
Common stock - held in treasury | (2,917,286) | (2,684,274) |
Common stock - outstanding | 14,383,913 | 14,540,556 |
Class B Common Stock [Member] | ||
Class of Stock [Line Items] | ||
Common stock - issued | 234,903 | 234,903 |
Common stock - held in treasury | (234,903) | (234,903) |
Common stock - outstanding | 0 | 0 |