Annual report pursuant to Section 13 and 15(d)

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

v2.4.1.9
Off-Balance-Sheet Risk and Concentration of Credit Risk (Detail) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Off-Balance-Sheet Risk and Concentration of Credit Risk [Abstract]    
Receivables from clearing broker $ 38,760us-gaap_ReceivablesFromClearingOrganizations $ 31,391us-gaap_ReceivablesFromClearingOrganizations