Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenues
Commissions	$ 102,772	$ 94,022
Information services	7,066	6,185
Post-trade services	4,576	2,456
Other	300	301
Total revenues	114,714	102,964
Expenses
Employee compensation and benefits	28,834	27,284
Depreciation and amortization	5,269	4,693
Technology and communications	5,779	4,585
Professional and consulting fees	5,057	4,279
Occupancy	3,337	1,404
Marketing and advertising	2,065	1,886
Clearing costs	1,725	1,327
General and administrative	2,475	2,348
Total expenses	54,541	47,806
Operating income	60,173	55,158
Other income (expense)
Investment income	1,168	747
Other, net	(328)	(298)
Total other income	840	449
Income before income taxes	61,013	55,607
Provision for income taxes	13,073	13,144
Net income	$ 47,940	$ 42,463
Net income per common share
Basic	$ 1.30	$ 1.15
Diluted	1.27	1.11
Cash dividends declared per common share	$ 0.42	$ 0.33
Weighted average shares outstanding
Basic	36,954	36,850
Diluted	37,886	38,112