Segment Analysis (Details 2) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Information concerning assets
Total Assets	$ 1,229,638	$ 3,303,556
Reportable segments
Information concerning assets
Total Assets	1,185,956	3,213,075
Investment Banking
Information concerning assets
Total Assets	15,907	10,916
MBS & Rates
Information concerning assets
Total Assets	1,026,987	2,929,879
Credit Products
Information concerning assets
Total Assets	40,952	29,930
ClearPoint
Information concerning assets
Total Assets	102,110	242,350
Other
Information concerning assets
Total Assets	95,345	126,358
Intersegment eliminations
Information concerning assets
Total Assets	$ (51,663)	$ (35,877)