Annual report pursuant to Section 13 and 15(d)

Off-Balance-Sheet Risk and Concentration of Credit Risk (Details)

v3.20.1
Off-Balance-Sheet Risk and Concentration of Credit Risk (Details) - USD ($)
$ in Thousands
Dec. 31, 2019
Dec. 31, 2018
Off-Balance-Sheet Risk and Concentration of Credit Risk [Abstract]    
Receivables from clearing brokers $ 23,086 $ 24,068