Annual report pursuant to Section 13 and 15(d)

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

v3.6.0.2
Off-Balance-Sheet Risk and Concentration of Credit Risk (Detail) - USD ($)
$ in Thousands
Dec. 31, 2016
Dec. 31, 2015
Off-Balance-Sheet Risk and Concentration of Credit Risk [Abstract]    
Receivables from clearing broker $ 41,492 $ 44,466