XML 44 R77.htm IDEA: XBRL DOCUMENT v2.4.0.6
Financial Instruments - Additional Information (Detail) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]    
Unrealized losses in net trading revenue $ 1,310 $ 1,084