Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash Flows from Operating Activities:
Net Income	$ 50,270	$ 25,459
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation expense	1,782	1,194
Intangible asset and other amortization	3,509	3,016
Stock-based compensation	5,983	5,366
Amortization of deferred commissions	10,032	8,089
Payments of deferred commissions	(13,993)	(7,744)
Realized and unrealized gains on trading securities	(1,887)	(1,639)
Realized and unrealized losses (gains) on investments of consolidated sponsored investment products	2,460	(541)
(Purchases) and sales of trading securities, net	(1,163)	691
Purchase of investments by consolidated sponsored investment products, net	(53,531)	(35,024)
Loss on disposal of fixed assets	29	17
Equity in earnings of affiliates	(98)
Deferred income taxes	29,001	15,952
Changes in operating assets and liabilities:
Accounts receivable	(9,327)	(5,747)
Prepaid expenses and other assets	(781)	(1,518)
Other current assets of consolidated sponsored investment products	(40,944)
Accounts payable and accrued liabilities	2,820	1,288
Other liabilities	966	3,511
Investment securities purchased of consolidated sponsored investment products	40,824	2,054
Other accrued liabilities of consolidated sponsored investment products	127	128
Net cash provided by operating activities	26,079	14,552
Cash Flows from Investing Activities:
Capital expenditures	(1,654)	(2,612)
Purchase of investment management contracts		(350)
Change in cash and cash equivalents of consolidated sponsored investment products due to deconsolidation	(666)
Acquisition of equity method investee	(3,364)
Purchase of available-for-sale securities	(145)	(232)
Net cash used in investing activities	(5,829)	(3,194)
Cash Flows from Financing Activities:
Contingent consideration paid for acquired investment management contracts	(420)	(510)
Repurchase of common shares	(19,704)	(3,059)
Proceeds from exercise of stock options	478	1,787
Payment of deferred financing costs	(26)	(563)
Taxes paid related to net share settlement of restricted stock units	(7,493)	(11,280)
Proceeds from issuance of common stock, net of issuance costs	191,800
Repayment of debt	(15,000)
Contributions of noncontrolling interests, net	11,396	235
Net cash provided by (used in) financing activities	161,031	(13,390)
Net increase (decrease) in cash and cash equivalents	181,281	(2,032)
Cash and cash equivalents, beginning of period	63,446	45,267
Cash and Cash Equivalents, end of period	244,727	43,235
Non-Cash Financing Activities:
Increase to noncontrolling interests due to net consolidation (deconsolidation) of sponsored investment products	4,414
Preferred stock conversion		$ 35,217