CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) Share data in Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Cash flows from operating activities:
Net (loss)/income	$ (4,684,000)	$ 7,205,000
Adjustments to reconcile net (loss)/income to net cash provided by operating activities:
Amortization of stock-based compensation	4,497,000	5,221,000
Deferred income taxes	3,697,000	5,586,000
Depreciation and amortization	487,000	475,000
Investment losses/(gains), net	(132,000)	686,000
Amortization of intangible assets	124,000	794,000
Gain from bargain purchase - ClearPoint Funding, Inc. acquisition		(2,330,000)
Changes in operating assets and liabilities:
Cash and securities segregated for regulatory purposes	7,612,000	(400,000)
Securities purchased under agreements to resell	(1,461,657,000)	(74,624,000)
Net receivable/payable from/to related parties		451,000
Net receivable from others	1,327,000	5,088,000
Financial instruments owned, at fair value	97,387,000	(104,255,000)
Income taxes receivable/payable, net	2,725,000	(807,000)
Other assets		1,434,000
Net payable to brokers, dealers and clearing organizations	(85,694,000)	129,669,000
Securities sold under agreements to repurchase	1,501,525,000	35,636,000
Securities sold, but not yet purchased, at fair value	48,503,000	32,545,000
Accounts payable and accrued expenses	(4,964,000)	(1,926,000)
Accrued compensation	(15,835,000)	(38,999,000)
Drafts payable	269,000	(744,000)
Net cash provided by operating activities	95,187,000	705,000
Cash flows from investing activities:
ClearPoint acquisition - net cash acquired (Refer to Note 11)		626,000
Purchases of office equipment and leasehold improvements	(360,000)	(535,000)
Return of capital - investments		515,000
Net cash (used in) provided by investing activities	(360,000)	606,000
Cash flows from financing activities:
Proceeds from secured borrowings	583,000,000	161,612,000
Repayments of secured borrowings	(679,416,000)	(157,474,000)
Purchases of treasury stock		(5,803,000)
Payment for employee tax withholdings on stock-based compensation	(2,403,000)	(5,041,000)
Excess tax benefits related to stock-based compensation	8,000	202,000
Net cash used in financing activities	(98,811,000)	(6,504,000)
Decrease in cash and cash equivalents	(3,984,000)	(5,193,000)
Cash and cash equivalents at beginning of the period	36,672,000	40,009,000
Cash and cash equivalents at the end of the period	32,688,000	34,816,000
NON CASH INVESTING AND FINANCING ACTIVITIES
Treasury stock, net of forfeitures, for stock-based compensation exercises and vesting (in shares)	6.9	0.4
Common stock for settlement of stock-based compensation awards (in shares)	0.1	2.3
Fair value of non-cash assets acquired in the ClearPoint Funding, Inc. acquisition (See Note 11)		51,600,000
Fair value of liabilities assumed in the ClearPoint Funding, Inc. acquisition (See Note 11)		$ 49,900,000