XML 214 R192.htm IDEA: XBRL DOCUMENT v3.21.1
Employee Benefit Plans and Similar Obligations - Summary of Share Based Compensation Plan (Plan 2018-2021) (Parenthetical) (Detail) - Plan 2018-21 [member]
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Average remaining life of plan 7 months    
Bottom of range [member]      
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Average remaining life of plan   7 months 7 months
Top of range [member]      
Disclosure of terms and conditions of share-based payment arrangement [line items]      
Average remaining life of plan   19 months 31 months