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Earnings and Dividends per Share (Additional Information) (Details) - shares
3 Months Ended 6 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Jun. 30, 2021
Jun. 30, 2020
Earnings and Dividends Per Share [Abstract]        
Number of options excluded from computation of diluted earnings per share 427,473 1,303,372 501,192 1,201,505