Other Assets (Details) (USD $)	3 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Other Assets
Collateral deposits	$ 5,108,000	$ 5,165,000
Prepaid expenses	3,640,000	2,761,000
Other	436,000	1,104,000
Total other assets	9,184,000	9,030,000
Non-cash impairment charge recorded on prepaid expenses associated with Company's exit of Investment Banking and Fixed Income businesses	$ 600,000