Consolidated Statements of Cash Flow - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash Flows from Operating Activities:
Net income (loss)	$ 119,963	$ 105,508	$ 76,080
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation expense, intangible asset and other amortization	38,853	39,643	33,426
Stock-based compensation	21,481	22,230	23,100
Amortization of deferred commissions	2,052	2,940	3,847
Payments of deferred commissions	(2,089)	(2,097)	(4,218)
Equity in earnings of equity method investments	(1,964)	(2,600)	(3,703)
Distributions from equity method investments	1,192	828	4,178
Sales (purchases) of investments, net	12,296	9,057	4,995
(Gain) loss on extinguishment of debt	(705)	0	0
Deferred taxes, net	6,332	5,982	10,429
Changes in operating assets and liabilities:
Accounts receivable, net and other assets	(9,698)	(1,382)	24,833
Accrued compensation and benefits, accounts payable, accrued liabilities and other liabilities	13,743	(2,991)	(24,714)
Operating activities of consolidated investment products ("CIP"):
Net cash provided by (used in) operating activities	(226,103)	(36,723)	(62,555)
Cash Flows from Investing Activities:
Capital expenditures and other asset purchases	(1,043)	(7,555)	(11,717)
Acquisition of business, net of cash acquired	0	0	(126,995)
Sale of available-for-sale securities	0	2,023	37,785
Purchases of available-for-sale securities	0	0	(20,188)
Net cash provided by (used in) investing activities	8,681	4,448	(121,228)
Cash Flows from Financing Activities:
Issuance of debt	0	0	105,000
Payment of long term debt	(79,086)	(54,851)	(23,776)
Payment of deferred financing costs	0	0	(3,810)
Repurchase of common shares	(32,500)	(40,000)	(27,501)
Preferred stock dividends paid	(2,084)	(8,338)	(8,338)
Common stock dividends paid	(22,800)	(16,977)	(14,038)
Proceeds from exercise of stock options	163	726	819
Taxes paid related to net share settlement of restricted stock units	(6,608)	(7,696)	(6,591)
Net subscriptions received from (redemptions/distributions paid to) noncontrolling interests	(7,263)	7,786	(5,512)
Net cash provided by (used in) financing activities	235,332	99,558	204,157
Net increase (decrease) in cash and cash equivalents	17,910	67,283	20,374
Cash, cash equivalents and restricted cash, beginning of year	321,939	254,656	234,282
Cash, cash equivalents and restricted cash, end of year	339,849	321,939	254,656
Supplemental Disclosure of Cash Flow Information
Interest paid	8,857	18,072	11,846
Income taxes paid, net	35,388	29,062	23,800
Supplemental Disclosure of Non-Cash Investing and Financing Activities
Capital expenditures	55	(1,791)	2,165
Conversion of preferred stock to common stock	115,000	0	0
Preferred stock dividends payable	0	2,084	2,084
Common stock dividends payable	6,218	4,562	3,849
Reconciliation of cash, cash equivalents and restricted cash
Cash, cash equivalents and restricted cash at end of year	339,849	254,656	254,656
Consolidated entity excluding consolidated investment products
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Realized and unrealized (gains) losses on investments, net	(7,128)	(6,855)	5,736
CIP
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Realized and unrealized (gains) losses on investments, net	(5,889)	(106)	18,706
Operating activities of consolidated investment products ("CIP"):
Purchases of investments by CIP	(1,304,723)	(1,029,746)	(1,106,991)
Sales of investments by CIP	883,888	810,749	874,279
Net proceeds (purchases) of short term investments by CIP	(1,092)	4,402	(552)
(Purchases) sales of securities sold short by CIP, net	158	1,241	209
Change in other assets of CIP	388	998	(628)
Change in liabilities of CIP	(4,330)	971	(1,567)
Amortization of discount on notes payable of CIP	11,169	4,505	0
Cash Flows from Investing Activities:
Change in cash and cash equivalents of CIP due to consolidation (deconsolidation), net	9,724	9,980	(113)
Cash Flows from Financing Activities:
Borrowings by CIP	779,982	414,605	857,404
Payments on borrowings by CIP	(394,472)	(195,697)	(669,500)
Supplemental Disclosure of Non-Cash Investing and Financing Activities
Increase (Decrease) to noncontrolling interests due to consolidation (deconsolidation) of CIP, net	$ 17,137	$ (13,926)	$ 56