Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenues
Commissions	$ 87,015	$ 86,239	$ 181,037	$ 165,332
Information and post-trade services	8,272	8,586	16,088	16,365
Investment income	840	517	1,587	935
Other	1,187	1,297	2,493	2,580
Total revenues	97,314	96,639	201,205	185,212
Expenses
Employee compensation and benefits	25,421	25,815	52,822	50,342
Depreciation and amortization	4,790	4,540	9,483	9,221
Technology and communications	4,822	4,277	9,407	8,581
Professional and consulting fees	4,086	4,245	8,365	8,107
Occupancy	1,422	1,225	2,826	2,386
Marketing and advertising	2,782	1,824	4,668	3,602
Clearing costs	1,517	1,953	2,844	3,719
General and administrative	2,901	2,209	5,610	4,333
Total expenses	47,741	46,088	96,025	90,291
Income before income taxes	49,573	50,551	105,180	94,921
Provision for income taxes	11,550	17,425	24,694	32,832
Net income	$ 38,023	$ 33,126	$ 80,486	$ 62,089
Net income per common share
Basic	$ 1.03	$ 0.90	$ 2.18	$ 1.69
Diluted	1.00	0.88	2.11	1.65
Cash dividends declared per common share	$ 0.33	$ 0.26	$ 0.66	$ 0.52
Weighted average shares outstanding
Basic	36,853	36,876	36,852	36,826
Diluted	38,077	37,748	38,095	37,710