Consolidated Statements of Financial Condition - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
ASSETS
Cash and cash equivalents	$ 246,322	$ 167,014
Investments, at fair value	240,105	239,521
Accounts receivable, net of allowance of $80 and $178 as of December 31, 2018 and 2017, respectively	57,535	52,636
Goodwill and intangible assets, net of accumulated amortization	62,675	63,059
Furniture, equipment, leasehold improvements and capitalized software, net of accumulated depreciation and amortization	63,010	38,548
Prepaid expenses and other assets	22,468	18,717
Deferred tax assets, net	3,424	1,737
Total assets	695,539	581,232
Liabilities
Accrued employee compensation	39,053	36,502
Income and other tax liabilities	16,432	13,061
Deferred revenue	2,810	2,660
Accounts payable, accrued expenses and other liabilities	29,366	14,241
Total liabilities	87,661	66,464
Commitments and Contingencies (Note 12)
Stockholders' equity
Additional paid-in capital	341,860	331,081
Treasury stock - Common stock voting, at cost, 2,900,432 and 2,781,323 shares as of December 31, 2018 and 2017, respectively	(184,962)	(159,791)
Retained earnings	463,252	353,583
Accumulated other comprehensive loss	(12,394)	(10,226)
Total stockholders' equity	607,878	514,768
Total liabilities and stockholders' equity	695,539	581,232
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	$ 122	$ 121