Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Revenues
Commissions	$ 81,456	$ 65,178	$ 246,788	$ 198,608
Information and post-trade services	7,322	7,671	23,687	22,982
Investment income	534	248	1,469	621
Other	959	1,095	3,539	4,243
Total revenues	90,271	74,192	275,483	226,454
Expenses
Employee compensation and benefits	23,914	21,002	74,256	62,769
Depreciation and amortization	4,325	4,642	13,546	13,857
Technology and communications	4,245	3,891	12,826	12,196
Professional and consulting fees	4,342	3,210	12,449	9,503
Occupancy	1,220	1,246	3,606	3,470
Marketing and advertising	2,140	1,304	5,742	4,260
General and administrative	3,731	3,544	11,783	9,485
Total expenses	43,917	38,839	134,208	115,540
Income before income taxes	46,354	35,353	141,275	110,914
Provision for income taxes	15,436	12,638	48,268	39,368
Net income	$ 30,918	$ 22,715	$ 93,007	$ 71,546
Net income per common share
Basic	$ 0.84	$ 0.62	$ 2.52	$ 1.95
Diluted	0.82	0.60	2.46	1.90
Cash dividends declared per common share	$ 0.26	$ 0.20	$ 0.78	$ 0.60
Weighted average shares outstanding
Basic	36,889	36,681	36,847	36,695
Diluted	37,792	37,643	37,738	37,636