Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash Flows from Operating Activities:
Net income	$ 13,745	$ 11,870
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation expense, intangible asset and other amortization	960	1,573
Stock-based compensation	3,491	3,270
Excess tax benefit from stock-based compensation	0	(130)
Payments of deferred commissions	(671)	(500)
Equity in earnings of equity method investments	(629)	(218)
Realized and unrealized (gains) losses on trading securities, net	(297)	658
Sales of trading securities, net	2,396	11,197
Deferred taxes, net	2,817	4,900
Purchases of investments by consolidated sponsored investment products
Accounts receivable, net and other assets	(13,013)	(4,944)
Accrued compensation and benefits, accounts payable, accrued liabilities and other liabilities	(24,305)	(35,710)
Net cash used in operating activities	(15,305)	(38,375)
Cash Flows from Investing Activities:
Capital expenditures	(369)	(591)
Equity method investment contributions	0	(759)
Purchases of available-for-sale securities	(66)	(60)
Net cash provided by (used in) investing activities	5,180	(1,307)
Cash Flows from Financing Activities:
Repayments on credit facility	(30,000)	0
Proceeds from issuance of mandatory convertible preferred stock, net of issuance costs	111,280	0
Proceeds from issuance of common stock, net of issuance costs	109,762	0
Common stock dividends paid	(2,894)	(3,911)
Repurchases of common shares	0	(15,000)
Proceeds from exercise of stock options	86	375
Taxes paid related to net share settlement of restricted stock units	(2,464)	(1,001)
Excess tax benefits from stock-based compensation	0	130
Payment of deferred financing costs	(61)	0
(Redemptions) Contributions of noncontrolling interests, net	(6,091)	19,928
Net cash provided by financing activities	179,191	1,549
Net increase (decrease) in cash and cash equivalents	169,066	(38,133)
Cash and cash equivalents, beginning of period	82,687	97,384
Cash and Cash Equivalents, End of Period	251,753	59,251
Non-Cash Investing Activities:
Change in accrual for capital expenditures	(166)	(153)
Non-Cash Financing Activities:
Decrease to noncontrolling interest due to consolidation and (deconsolidation) of consolidated sponsored investment products	13,083	(52,874)
Common stock dividends payable	3,145	4,173
Preferred stock dividends payable	2,084	0
Accrued stock issuance costs	886	0
Consolidated Sponsored Investment Products
Adjustments to reconcile net income to net cash used in operating activities:
Realized and unrealized (gains) losses on trading securities, net	(4,139)	(683)
Purchases of investments by consolidated sponsored investment products	(32,805)	(112,013)
Sales of investments	39,706	103,196
Net purchases of short term investments by consolidated sponsored investment products	(1,735)	(12,728)
Purchases of securities sold short by consolidated sponsored investment products, net	(20)	(3,655)
Change in cash pledged or on deposit of consolidated sponsored investment products	(123)	1,682
Purchases of investments by consolidated sponsored investment products
Purchases of securities sold short by consolidated sponsored investment products, net	118	(1,292)
Change in liabilities of consolidated investment product	128	618
Cash Flows from Investing Activities:
Increase in cash and cash equivalents of consolidated sponsored investment products due to consolidation, net	5,615	103
Cash Flows from Financing Activities:
Borrowings (Payments) on borrowings by consolidated sponsored investment products, net	73	(1,839)
Consolidated Investment Product
Adjustments to reconcile net income to net cash used in operating activities:
Amortization of deferred commissions	516	763
Realized and unrealized (gains) losses on trading securities, net	(718)	(2,235)
Purchases of investments by consolidated sponsored investment products	(59,673)	(7,481)
Sales of investments	58,485	3,402
Purchases of investments by consolidated sponsored investment products
Purchases of securities sold short by consolidated sponsored investment products, net	417	(163)
Change in liabilities of consolidated investment product	44	248
Cash Flows from Financing Activities:
Borrowings of debt of consolidated investment product	0	2,867
Repayment of notes payable by consolidated investment product	$ (500)	$ 0