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Financial Instruments - Additional Information (Detail) - USD ($)
$ in Thousands
Dec. 31, 2020
Dec. 31, 2019
Financial Instruments Owned And Pledged As Collateral [Line Items]    
Fair value transfers between levels $ 0 $ 0
Fair Value Inputs Level 3 [Member]    
Financial Instruments Owned And Pledged As Collateral [Line Items]    
Financial instruments net $ 0 $ 0