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Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($)
9 Months Ended
Sep. 30, 2021
Dec. 31, 2020
Goodwill [Line Items]    
Changes in goodwill $ 0  
Domain Names [Member]    
Goodwill [Line Items]    
Unamortized Intangible Assets $ 571,000 $ 571,000