Consolidated Statements of Financial Condition (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
ASSETS
Cash and cash equivalents	$ 135,468	$ 128,908
Securities available-for-sale, at fair value	14,479	51,208
Accounts receivable, net of allowance of $131 and $75 as of June 30, 2013 and December 31, 2012, respectively	41,826	31,044
Goodwill and intangible assets, net of accumulated amortization	71,447	33,134
Furniture, equipment, leasehold improvements and capitalized software, net of accumulated depreciation and amortization	26,443	18,009
Prepaid expenses and other assets	11,204	8,096
Deferred tax assets, net	4,511	9,442
Total assets	305,378	279,841
Liabilities
Accrued employee compensation	12,509	19,916
Deferred revenue	5,437	4,864
Accounts payable, accrued expenses and other liabilities	16,868	12,344
Total liabilities	34,814	37,124
Commitments and Contingencies (Note 11)
Stockholders' equity
Preferred stock
Additional paid-in capital	286,816	283,609
Treasury stock-Common stock voting, at cost, 1,495,159 shares as of June 30, 2013 and December 31, 2012	(32,273)	(32,273)
Retained earnings (deficit)	19,467	(5,644)
Accumulated other comprehensive loss	(3,565)	(3,093)
Total stockholders' equity	270,564	242,717
Total liabilities and stockholders' equity	305,378	279,841
Series A Preferred Stock [Member]
Stockholders' equity
Preferred stock
Common Stock Voting [Member]
Stockholders' equity
Common stock	119	118
Total stockholders' equity	119	118
Common Stock Non-Voting [Member]
Stockholders' equity
Common stock