Earnings Per Share - Additional Information (Detail) - shares |
3 Months Ended | 9 Months Ended | ||
---|---|---|---|---|
Sep. 30, 2018 |
Sep. 30, 2017 |
Sep. 30, 2018 |
Sep. 30, 2017 |
|
Earnings Per Share, Basic and Diluted, Other Disclosures [Abstract] | ||||
Shares of common stock outstanding | 5,020,021 | 5,123,186 | 5,051,306 | 5,123,186 |