Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash Flows from Operating Activities:
Net income (loss)	$ 47,056	$ 13,773
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation expense, intangible asset and other amortization	13,641	4,894
Stock-based compensation	12,073	9,490
Amortization of deferred commissions	1,646	1,072
Payments of deferred commissions	(2,600)	(1,389)
Equity in earnings of equity method investments	(1,801)	(679)
Distributions from equity method investments	669	0
Sales (purchases) of trading securities, net	6,150	5,558
Deferred taxes, net	1,374	(576)
Changes in operating assets and liabilities:
Accounts receivable, net and other assets	(5,469)	(7,359)
Accrued compensation and benefits, accounts payable, accrued liabilities and other liabilities	(45,713)	(22,465)
Operating activities of consolidated investment products (CIP):
Net cash provided by (used in) operating activities	(154,513)	54,502
Cash Flows from Investing Activities:
Capital expenditures	(2,274)	(678)
Acquisition of business (cash paid $471.4 million, less cash acquired $77.6 million)	0	(393,784)
Sale of available-for-sale securities	37,785	0
Purchases of available-for-sale securities	(20,188)	(130)
Net cash provided by (used in) investing activities	15,323	(389,126)
Cash Flows from Financing Activities:
Issuance of debt	0	260,000
Repayments on debt	(1,300)	(30,271)
Payment of deferred financing costs	(3,548)	(15,520)
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	(6,735)	(6,060)
Preferred stock dividends paid	(4,168)	(2,084)
Repurchases of common shares	(7,500)	0
Stock options exercised	698	86
Taxes paid related to net share settlement of restricted stock units	(5,238)	(3,029)
Contributions (redemptions) of noncontrolling interests, net	(2,140)	7,733
Net cash provided by (used in) financing activities	85,436	430,846
Net increase (decrease) in cash and cash equivalents	(53,754)	96,222
Cash and cash equivalents, beginning of period	234,282	83,671
Cash and Cash Equivalent, End of Period	180,528	179,893
Non-Cash Investing Activities:
Change in accrual for capital expenditures	(439)	(174)
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	4,569	3,248
Preferred stock dividends payable	2,084	2,084
Accrued stock issuance costs	0	334
Reconciliation of cash and cash equivalents
Cash and cash equivalents	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	(1,398)	(1,584)
Cash Flows from Financing Activities:
Cash and cash equivalents, beginning of period	132,150
Cash and Cash Equivalent, End of Period	138,827
Reconciliation of cash and cash equivalents
Cash and cash equivalents	132,150
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	(608)	(2,879)
Operating activities of consolidated investment products (CIP):
Purchases of investments by CIP	(641,236)	(150,500)
Sales of investments by CIP	465,213	205,347
Net purchases of short term investments by CIP	97	265
Sales (purchases) of securities sold short by CIP, net	187	153
Change in other assets of CIP	(829)	1,589
Change in liabilities of CIP	(2,965)	(208)
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:
Proceeds from issuance of notes payable by CIP	784,867	0
Repayment of notes payable by CIP	(669,500)	$ (500)
Cash and cash equivalents, beginning of period	101,315
Cash and Cash Equivalent, End of Period	40,755
Reconciliation of cash and cash equivalents
Cash and cash equivalents	$ 101,315