CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues
Trading revenues, net	$ 230,471	$ 92,556	$ 415,495	$ 333,737
Commissions and fees	109,079	25,542	164,391	79,487
Interest, net	(177)	(781)	(970)	(1,998)
Investment income and other, net	128,446	13,285	119,207	14,015
Total revenues	467,819	130,602	698,123	425,241
Expenses
Employee compensation and benefits	129,631	31,875	236,983	111,395
Execution and clearance fees	81,023	42,267	167,931	144,656
Communications and data processing	44,046	21,681	86,040	67,380
Interest	23,870	706	26,515	2,002
Depreciation and amortization	20,091	7,574	36,004	27,180
Payments for order flow	16,431	717	17,468	2,128
Professional fees	9,077	2,575	38,928	7,690
Occupancy and equipment rentals	8,898	3,240	15,454	8,865
Business development	2,644	6	2,686	19
Writedown of assets and lease loss accrual	936	0	4,248	0
Other	11,318	5,349	30,028	19,002
Total expenses	347,965	115,990	662,285	390,317
Income from continuing operations before income taxes	119,854	14,612	35,838	34,924
Income tax (benefit) expense	(107,767)	4,805	(102,478)	10,368
Income from continuing operations, net of tax	227,621	9,807	138,316	24,556
Loss from discontinued operations, net of tax	(784)	0	(784)	0
Net income	$ 226,837	$ 9,807	$ 137,532	$ 24,556
Basic earnings per share from continuing operations (in dollars per share)	$ 1.99	$ 0.21	$ 2.02	$ 0.49
Diluted earnings per share from continuing operations (in dollars per share)	$ 1.98	$ 0.21	$ 2.01	$ 0.49
Basic loss per share from discontinued operations (in dollars per share)	$ (0.01)	$ 0.00	$ (0.01)	$ 0.00
Diluted loss per share from discontinued operations (in dollars per share)	$ (0.01)	$ 0.00	$ (0.01)	$ 0.00
Basic earnings per share (in dollars per share)	$ 1.99	$ 0.21	$ 2.00	$ 0.49
Diluted earnings per share (in dollars per share)	$ 1.98	$ 0.21	$ 2.00	$ 0.49
Shares used in computation of basic earnings (loss) per share (in shares)	114,113	46,411	68,632	49,619
Shares used in computation of diluted earnings (loss) per share (in shares)	114,773	46,411	68,855	49,619