Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Revenues:
Trading income, net	$ 139,574	$ 186,289
Interest and dividends income	4,874	4,268
Technology services	2,779	2,081
Other, net	60
Total revenue	147,287	192,638
Operating Expenses:
Brokerage, exchange and clearance fees, net	52,770	59,725
Communication and data processing	18,207	17,722
Employee compensation and payroll taxes	21,347	22,557
Interest and dividends expense	12,280	13,537
Operations and administrative	4,978	4,919
Depreciation and amortization	6,757	7,727
Amortization of purchased intangibles and acquired capitalized software	53	53
Charges related to share-based compensation at IPO	185	595
Financing interest expense on long-term borrowings	6,828	7,101
Total operating expenses	123,405	133,936
Income before income taxes and noncontrolling interest	23,882	58,702
Provision for income taxes	2,808	7,346
Net income	21,074	51,356
Noncontrolling interest	(16,494)	(41,008)
Net income available for common stockholders	$ 4,580	$ 10,348
Earnings per share
Basic (in dollars per share)	$ 0.10	$ 0.27
Diluted (in dollars per share)	$ 0.10	$ 0.26
Weighted average common shares outstanding
Basic (in shares)	40,398,381	38,210,209
Diluted (in shares)	40,398,381	38,489,489
Comprehensive income
Net income	$ 21,074	$ 51,356
Other comprehensive income (loss)
Foreign currency translation adjustment, net of taxes	785	2,494
Comprehensive income	21,859	53,850
Less: Comprehensive income attributable to non-controlling interests	(17,044)	(42,801)
Comprehensive income attributable to common stockholders	$ 4,815	$ 11,049