Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash Flows from Operating Activities:
Net income (loss)	$ 74,987	$ 34,296
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation expense, intangible asset and other amortization	23,147	11,621
Stock-based compensation	16,914	14,970
Amortization of deferred commissions	2,734	1,666
Payments of deferred commissions	(3,839)	(2,104)
Equity in earnings of equity method investments	(2,358)	(1,150)
Distributions received from equity method investments	4,032	911
Sales (purchases) of trading securities, net	5,571	3,859
Deferred taxes, net	9,710	6,056
Loss on disposal of fixed assets	25	345
Changes in operating assets and liabilities:
Accounts receivable, net and other assets	10,343	(9,466)
Accrued compensation and benefits, accounts payable, accrued liabilities and other liabilities	(39,560)	(2,147)
Operating activities of consolidated investment products (CIP):
Net cash provided by (used in) operating activities	(101,689)	(104,045)
Cash Flows from Investing Activities:
Capital expenditures	(2,516)	(1,243)
Acquisition of businesses (cash paid of $129.5 million, less cash acquired of $2.5 million in 2018 and cash paid of $471.4 million, less cash acquired of $77.6 million in 2017)	(126,995)	(393,446)
Sale of available-for-sale securities	37,785	0
Purchases of available-for-sale securities	(20,188)	(194)
Net cash provided by (used in) investing activities	(111,914)	(389,417)
Cash Flows from Financing Activities:
Issuance of debt	105,000	260,000
Repayments on debt	(12,863)	(30,970)
Payment of deferred financing costs	(3,810)	(15,549)
Proceeds from issuance of mandatory convertible preferred stock, net of issuance costs	0	111,004
Proceeds from issuance of common stock, net of issuance costs	0	109,487
Common stock dividends paid	(10,093)	(9,352)
Preferred stock dividends paid	(6,253)	(4,169)
Repurchases of common shares	(12,501)	(7,502)
Stock options exercised	719	106
Taxes paid related to net share settlement of restricted stock units	(6,517)	(3,436)
Contributions (redemptions) of noncontrolling interests, net	(2,159)
Contributions (redemptions) of noncontrolling interests, net		18,448
Net cash provided by (used in) financing activities	199,497	796,576
Net increase (decrease) in cash, cash equivalents and restricted cash	(14,106)	303,114
Cash, cash equivalents and restricted cash, beginning of period	234,282	83,671
Cash, Cash Equivalent and Restricted Cash, End of Period	220,176	386,785
Non-Cash Investing Activities:
Change in accrual for capital expenditures	1,906	96
Non-Cash Financing Activities:
Increase (decrease) to noncontrolling interest due to consolidation (deconsolidation) of CIP, net	0	11,286
Stock issued for acquisition of business	0	21,738
Contingent consideration for acquisition of business	0	51,690
Common stock dividends payable	3,930	4,234
Preferred stock dividends payable	2,085	2,084
Accrued stock issuance costs	0	332
Reconciliation of cash, cash equivalents and restricted cash
Cash, Cash Equivalent and Restricted Cash, End of Period	234,282	83,671
Consolidated entity excluding consolidated investment products
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Realized and unrealized (gains) losses on trading securities, net	(752)	(3,117)
Consolidated investment products
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Realized and unrealized (gains) losses on trading securities, net	2,108	(16,875)
Operating activities of consolidated investment products (CIP):
Purchases of investments by CIP	(857,999)	(527,214)
Sales of investments by CIP	655,335	377,238
Net purchases of short term investments by CIP	111	565
Change in other assets of CIP	(609)	417
Change in liabilities of CIP	(1,589)	1,042
Amortization of discount on notes payable of CIP	0	5,042
Cash Flows from Investing Activities:
Change in cash and cash equivalents of CIP due to consolidation, net	0	5,466
Cash Flows from Financing Activities:
Payments on borrowings by CIP	(669,500)	(105,000)
Borrowings (payments) on borrowings by CIP	817,474	0
Proceeds from issuance of notes payable by CIP	0	474,009
Repayment of notes payable by CIP	$ 0	$ (500)