CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues
Trading revenues, net	$ 668,003	$ 803,181	$ 837,357
Commissions and fees	391,419	376,673	437,022
Interest, net	1,625	(2,128)	621
Investment income and other, net	393,365	421,384	41,232
Total revenues	1,454,412	1,599,110	1,316,232
Expenses
Employee compensation and benefits	295,120	405,609	437,269
Execution and clearance fees	295,312	265,186	305,177
Communications and data processing	147,986	139,263	150,595
Depreciation and amortization	88,790	90,231	81,448
Payments for order flow	54,765	61,741	70,183
Collateralized financing interest	40,423	34,678	27,860
Occupancy and equipment rentals	37,875	30,128	32,707
Debt interest expense	37,216	40,291	36,121
Professional fees	19,827	27,055	25,596
Business development	5,324	8,479	9,763
Debt extinguishment charges	0	25,006	9,552
Writedown of assets and other real estate related charges	0	56,642	8,625
Other	35,346	34,839	36,149
Total expenses	1,057,984	1,219,148	1,231,045
Income from continuing operations before income taxes	396,428	379,962	85,187
Income tax expense	140,731	130,858	22,753
Income from continuing operations, net of tax	255,697	249,104	62,434
Loss from discontinued operations, net of tax	0	0	(1,332)
Net income	$ 255,697	$ 249,104	$ 61,102
Basic earnings per share from continuing operations (in dollars per share)	$ 3.03	$ 2.48	$ 0.55
Diluted earnings per share from continuing operations (in dollars per share)	2.97	2.42	0.54
Basic loss per share from discontinued operations (in dollars per share)	0.00	0.00	(0.01)
Diluted loss per share from discontinued operations (in dollars per share)	0.00	0.00	(0.01)
Basic earnings per share (in dollars per share)	3.03	2.48	0.54
Diluted earnings per share (in dollars per share)	$ 2.97	$ 2.42	$ 0.52
Shares used in computation of basic earnings per share	84,405	100,437	112,854
Shares used in computation of diluted earnings per share	86,160	102,922	116,534