Consolidated Statements of Financial Condition - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
ASSETS
Cash and cash equivalents	$ 286,179	$ 246,322
Investments, at fair value	231,895	240,105
Accounts receivable, net of allowance of $76 and $80 as of June 30, 2019 and December 31, 2018, respectively	66,332	57,535
Goodwill and intangible assets, net of accumulated amortization	62,483	62,675
Furniture, equipment, leasehold improvements and capitalized software, net of accumulated depreciation and amortization	64,206	63,010
Operating lease right-of-use assets	76,722
Prepaid expenses and other assets	22,597	22,468
Deferred tax assets, net	1,595	3,424
Total assets	812,009	695,539
Liabilities
Accrued employee compensation	26,669	39,053
Income and other tax liabilities	12,860	16,432
Deferred revenue	3,810	2,810
Accounts payable, accrued expenses and other liabilities	17,050	29,366
Operating lease liabilities	89,712
Total liabilities	150,101	87,661
Commitments and Contingencies (Note 11)
Stockholders' equity
Common stock	122	122
Additional paid-in capital	341,446	341,860
Treasury stock - Common stock voting, at cost, 2,934,752 and 2,900,432 shares as of June 30, 2019 and December 31, 2018, respectively	(193,632)	(184,962)
Retained earnings	525,430	463,252
Accumulated other comprehensive loss	(11,458)	(12,394)
Total stockholders' equity	661,908	607,878
Total liabilities and stockholders' equity	812,009	695,539
Undefined Preferred Stock [Member]
Stockholders' equity
Preferred stock
Series A Preferred Stock [Member]
Stockholders' equity
Preferred stock