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Computation of Earnings Per Share - Additional Information (Detail) - shares
3 Months Ended 9 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Earnings Per Share [Abstract]        
Common stock excluded from the calculation of diluted earnings per share 103,920 45,150 103,920 45,150