Discontinued Operations (Details) (USD $)	3 Months Ended			9 Months Ended
	Sep. 30, 2013	Mar. 31, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Discontinued Operations
Total net revenue	$ 419,000		$ 42,955,000	$ 28,674,000	$ 151,906,000
Total expenses (excluding restructuring expense)	1,403,000		40,278,000	49,888,000	171,691,000
Subtotal	(984,000)		2,677,000	(21,214,000)	(19,785,000)
Restructuring expense	(4,744,000)			(50,830,000)
(Loss)/income from discontinued operations before income taxes	(5,728,000)		2,677,000	(72,044,000)	(19,785,000)
Income tax expense					1,802,000
(Loss)/income from discontinued operations, net of taxes	(5,728,000)		2,677,000	(72,044,000)	(21,587,000)
Other items reclassified from continuing operations
Discontinued Operations
Total net revenue	2,000		799,000	572,000	4,381,000
Total expenses (excluding restructuring expense)	490,000		3,127,000	5,103,000	31,076,000
Expenses, net of revenues	(488,000)		(2,328,000)	(4,531,000)	(26,695,000)
Investment Banking
Discontinued Operations
Total net revenue			1,499,000	15,034,000	14,762,000
Total expenses (excluding restructuring expense)	257,000		1,756,000	12,863,000	12,245,000
Expenses, net of revenues	(257,000)		(257,000)	2,171,000	2,517,000
MBS & Rates
Discontinued Operations
Total net revenue	(68,000)		8,943,000	(4,412,000)	34,556,000
Total expenses (excluding restructuring expense)	321,000		7,129,000	10,823,000	29,000,000
Expenses, net of revenues	(389,000)		1,814,000	(15,235,000)	5,556,000
Credit Products
Discontinued Operations
Total net revenue	485,000		18,804,000	13,049,000	58,393,000
Total expenses (excluding restructuring expense)	204,000		14,865,000	14,413,000	53,857,000
Expenses, net of revenues	281,000		3,939,000	(1,364,000)	4,536,000
ClearPoint
Discontinued Operations
Loss recognized from discontinued operations		1,100,000
Total net revenue			12,899,000	4,355,000	39,760,000
Total expenses (excluding restructuring expense)	63,000		13,423,000	6,499,000	45,638,000
Expenses, net of revenues	(63,000)		(524,000)	(2,144,000)	(5,878,000)
Equities division
Discontinued Operations
Total net revenue			11,000	76,000	54,000
Total expenses (excluding restructuring expense)	68,000		(22,000)	187,000	(125,000)
Expenses, net of revenues	$ (68,000)		$ 33,000	$ (111,000)	$ 179,000