Consolidated Statements of Financial Condition - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
ASSETS
Cash and cash equivalents	$ 260,953	$ 246,322
Investments, at fair value	222,458	240,105
Accounts receivable, net of allowance of $114 and $80 as of March 31, 2019 and December 31, 2018, respectively	70,946	57,535
Goodwill and intangible assets, net of accumulated amortization	62,579	62,675
Furniture, equipment, leasehold improvements and capitalized software, net of accumulated depreciation and amortization	61,047	63,010
Operating lease right-of-use assets	78,190
Prepaid expenses and other assets	17,219	22,468
Deferred tax assets, net	1,417	3,424
Total assets	774,809	695,539
Liabilities
Accrued employee compensation	16,699	39,053
Income and other tax liabilities	18,857	16,432
Deferred revenue	3,545	2,810
Accounts payable, accrued expenses and other liabilities	13,717	29,366
Operating lease liabilities	90,845
Total liabilities	143,663	87,661
Commitments and Contingencies (Note 11)
Stockholders' equity
Additional paid-in capital	335,425	341,860
Treasury stock - Common stock voting, at cost, 2,921,902 and 2,900,432 shares as of March 31, 2019 and December 31, 2018, respectively	(190,146)	(184,962)
Retained earnings	496,562	463,252
Accumulated other comprehensive loss	(10,817)	(12,394)
Total stockholders' equity	631,146	607,878
Total liabilities and stockholders' equity	774,809	695,539
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	$ 122