Quarterly report pursuant to Section 13 or 15(d)

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

v3.19.1
Off-Balance-Sheet Risk and Concentration of Credit Risk (Detail)
$ in Thousands
3 Months Ended
Mar. 31, 2019
USD ($)
clearing_broker
Dec. 31, 2018
USD ($)
Risks and Uncertainties [Abstract]    
Number of clearing brokers | clearing_broker 2  
Receivables from clearing brokers | $ $ 42,059 $ 24,068