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Financial instruments owned - Additional Information (Detail) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2023
Mar. 31, 2022
Financial Instruments Owned at Fair Value [Member]    
Debt and Equity Securities, FV-NI [Line Items]    
Debt and Equity Securities, Gain (Loss) $ 4,722 $ 4,316