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Computation of Earnings Per Share - Additional Information (Detail) - shares
3 Months Ended 9 Months Ended
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2020
Sep. 30, 2019
Earnings Per Share [Abstract]        
Common stock excluded from the calculation of diluted earnings per share 0 103,290 53,025 103,290