XML 109 R36.htm IDEA: XBRL DOCUMENT

Financial Instruments - Securities Owned and Securities Sold, But Not Yet Purchased at Fair Value (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Securities Owned	$ 868,890	$ 759,742
Securities Sold	111,076	173,450
US Government, Agency, and Sovereign Obligations [Member]
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Securities Owned	586,095	525,255
Securities Sold	55,026	131,930
Corporate Debt and Other Obligations [Member]
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Securities Owned	11,979	14,428
Securities Sold	3,187	1,858
Mortgage and Other Asset-Backed Securities [Member]
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Securities Owned	3,246	2,920
Securities Sold	5	18
Municipal Obligations [Member]
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Securities Owned	93,155	59,010
Securities Sold	795	467
Convertible Bonds [Member]
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Securities Owned	60,851	49,130
Securities Sold	8,230	8,868
Corporate Equities [Member]
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Securities Owned	45,132	43,708
Securities Sold	43,757	29,884
Other [Member]
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Securities Owned	68,432	65,291
Securities Sold	$ 76	$ 425