Office Equipment and Leasehold Improvements (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Office equipment and leasehold improvements
Total	$ 4,146,000		$ 4,146,000		$ 11,135,000
Less: accumulated depreciation and amortization	(3,374,000)		(3,374,000)		(5,824,000)
Total office equipment and leasehold improvements, net	772,000		772,000		5,311,000
Non-cash impairment charge related to office equipment and leasehold improvements of Investment Banking and Fixed Income businesses	3,500,000
Depreciation and amortization expense from continuing operations	300,000	500,000	623,000	971,000
Communications and data processing equipment
Office equipment and leasehold improvements
Total	1,584,000		1,584,000		5,149,000
Furniture and fixtures
Office equipment and leasehold improvements
Total	1,219,000		1,219,000		3,334,000
Leasehold improvements
Office equipment and leasehold improvements
Total	750,000		750,000		1,802,000
Software
Office equipment and leasehold improvements
Total	$ 593,000		$ 593,000		$ 850,000