Annual report pursuant to Section 13 and 15(d)

Selected Balance Sheet Data - Schedule of Advances and Loans, Net (Detail)

v3.20.4
Selected Balance Sheet Data - Schedule of Advances and Loans, Net (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Advances And Loans and Commissions Receivable Allowance For Credit Losses [Line Items]    
Beginning balance $ 512 $ 514
Credit loss expense 126 114
Write-offs (75) (116)
Ending balance 563 512
Beginning balance 0 0
Credit loss expense 62 0
Write-offs 0 0
Ending balance 94 0
Beginning balance 512 514
Credit loss expense 188 114
Write-offs (75) (116)
Ending balance 657 512
Accounting Standards Update 2016-13 [Member]    
Advances And Loans and Commissions Receivable Allowance For Credit Losses [Line Items]    
Beginning balance 32  
Ending balance   32
Beginning balance $ 544  
Ending balance   $ 544