Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Revenues:
Trading income, net	$ 186,289	$ 213,930
Interest and dividends income	4,268	5,182
Technology services	2,081	2,416
Total revenue	192,638	221,528
Operating Expenses:
Brokerage, exchange and clearance fees, net	59,725	61,138
Communication and data processing	17,722	17,943
Employee compensation and payroll taxes	22,557	26,900
Interest and dividends expense	13,537	9,566
Operations and administrative	4,919	8,491
Depreciation and amortization	7,727	9,663
Amortization of purchased intangibles and acquired capitalized software	53	53
Charges related to share-based compensation at IPO	595
Financing interest expense on senior secured credit facility	7,101	7,602
Total operating expenses	133,936	141,356
Income before income taxes and noncontrolling interest	58,702	80,172
Provision for income taxes	7,346	2,728
Net income	51,356	77,444
Noncontrolling interest	(41,008)
Net income available for common stockholders	$ 10,348
Earnings per share
Basic (in dollars per share)	$ 0.27
Diluted (in dollars per share)	$ 0.26
Weighted average common shares outstanding
Basic (in shares)	38,210,209
Diluted (in shares)	38,489,489
Comprehensive income
Net income	$ 51,356	77,444
Other comprehensive income (loss)
Foreign exchange translation adjustment, net of taxes	2,494	(4,633)
Comprehensive income	53,850	$ 72,811
Less: Comprehensive income attributable to non-controlling interests	(42,801)
Comprehensive income attributable to common stockholders	$ 11,049