Consolidated Statements of Financial Condition - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
ASSETS
Cash and cash equivalents	$ 138,992	$ 168,243
Investments, at fair value	237,221	194,404
Accounts receivable, net of allowance of $71 and $82 as of September 30, 2017 and December 31, 2016, respectively	63,027	50,668
Goodwill and intangible assets, net of accumulated amortization	63,155	63,443
Furniture, equipment, leasehold improvements and capitalized software, net of accumulated depreciation and amortization	35,321	31,104
Prepaid expenses and other assets	16,174	11,618
Deferred tax assets, net	8,457	8,562
Total assets	562,347	528,042
Liabilities
Accrued employee compensation	31,027	34,783
Income and other tax liabilities	4,507	7,582
Deferred revenue	3,191	2,515
Accounts payable, accrued expenses and other liabilities	12,714	15,149
Total liabilities	51,439	60,029
Commitments and Contingencies (Note 10)
Stockholders' equity
Additional paid-in capital	342,113	342,311
Treasury stock - Common stock voting, at cost, 2,748,823 and 2,562,585 shares as of September 30, 2017 and December 31, 2016, respectively	(153,682)	(117,330)
Retained earnings	332,506	255,140
Accumulated other comprehensive loss	(10,150)	(12,228)
Total stockholders' equity	510,908	468,013
Total liabilities and stockholders' equity	562,347	528,042
Undefined Preferred Stock [Member]
Stockholders' equity
Preferred stock
Series A Preferred Stock [Member]
Stockholders' equity
Preferred stock
Voting Common Stock [Member]
Stockholders' equity
Common stock	$ 121	$ 120