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Stock-Based Compensation (Stock Options) - Additional Information (Detail) - USD ($)
6 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]    
Unrecognized compensation expense related to stock options $ 0  
Number of Stock options, granted 0 0
Aggregate intrinsic value based on fair market value $ 4,721,000  
Total pre-tax intrinsic value of options exercised $ 588,000