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Recent Accounting Pronouncements - Additional Information (Detail)
 3 Months Ended 9 Months Ended
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2020
Sep. 30, 2019
Summary Of Significant Accounting Policies [Line Items]        
Loan modifications that would have been previously treated as TDRs 0 0 0 0
Accounting Standards Update 2017-04 [Member]        
Summary Of Significant Accounting Policies [Line Items]        
Change in Accounting Principle, Accounting Standards Update, Adopted [true false] true   true  
Change in Accounting Principle, Accounting Standards Update, Adoption Date Jan. 01, 2020   Jan. 01, 2020  
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false] true   true  
Accounting Standards Update 2018-13 [Member]        
Summary Of Significant Accounting Policies [Line Items]        
Change in Accounting Principle, Accounting Standards Update, Adopted [true false] true   true  
Change in Accounting Principle, Accounting Standards Update, Adoption Date Jan. 01, 2020   Jan. 01, 2020  
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false] true   true