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Related Parties - Composition of Board of Directors and Key Management Personnel (Detail)
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Disclosure of transactions between related parties [line items]    
Number of board of directors and key management personnel 33 34
Board Of Directors [member]    
Disclosure of transactions between related parties [line items]    
Number of board of directors and key management personnel 22 24
Senior managers of key management personnel [member]    
Disclosure of transactions between related parties [line items]    
Number of board of directors and key management personnel 11 10