Consolidated Statements of Cash Flows - USD ($) $ / shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2020		Sep. 30, 2019
Cash flows from operating activities:
Net income (loss)	$ 104,353		$ 26,596
Adjustments to reconcile net income (loss) to net cash provided by / (used in) operating activities:
Depreciation and amortization	17,324		14,990
Goodwill Impairment	0		4,100
Amortization of debt issuance costs (premium)	1,023		804
Amortization of debt discount	3,393		3,511
Noncash lease expense	(1,490)		(2,607)
Share-based compensation	35,287		27,224
Change in deferred taxes	48,056		8,420
Net loss (gain) on disposal of fixed assets	0		367
Purchases of securities owned, at fair value	(1,275,400)		(1,405,478)
Proceeds from sales of securities owned, at fair value	1,318,623		1,282,527
Proceeds from sales of securities sold, not yet purchased, at fair value	729,526		902,271
Payments to cover securities sold, not yet purchased, at fair value	(745,683)		(939,072)
Proceeds from other investments	21,964		19,693
Net (gains) losses on securities, derivatives and other investments	(80,533)		(57,808)
Consolidated Funds
Purchases of securities owned, at fair value	(1,912,137)		(2,016,225)
Proceeds from sales of securities owned, at fair value	1,793,399		1,880,160
Purchases of other investments	(2,090)		(2,798)
Proceeds from other investments	6,734		23,865
Net realized and unrealized (gains) losses on investments and other transactions	27,216		(51,925)
(Increase) decrease in operating assets:
Securities owned, at fair value, held at broker-dealer	603,885		(250,579)
Receivable on derivative contracts, at fair value	4,783		(14,629)
Securities borrowed	(517,987)		(820,241)
Deposits with clearing organizations, brokers and banks	1,680		(2,027)
Receivable from brokers, dealers and clearing organizations	(709,126)		68,479
Receivable from customers, net of allowance	22,439		(8,268)
Fees receivable, net of allowance	(11,876)		17,707
Due from related parties	3,086		6,020
Other assets	69,185		1,038
Consolidated Funds
Cash and cash equivalents	8,989		34,809
Receivable on derivative contracts, at fair value	(19,710)		531
Receivable from brokers	(961)		(9,579)
Other assets	273		10
Increase (decrease) in operating liabilities:
Securities sold, not yet purchased, at fair value, held at broker dealer	2,302		191,640
Securities sold under agreement to repurchase	(17,026)		23,772
Payable for derivative contracts, at fair value	1,293		16,672
Securities loaned	(274,949)		924,795
Payable to brokers, dealers and clearing organizations	41,832		42,281
Payable to customers	720,915		(88)
Commission management payable	46,158		(6,146)
Compensation payable	116,035		(92,903)
Fees payable	60,311		11,060
Due to related parties	24		(4,402)
Accounts payable, accrued expenses and other liabilities	37,729		(2,679)
Consolidated Funds
Contributions received in advance	450		0
Payable to brokers	8,560		(8,355)
Payable for derivative contracts, at fair value	11,967		6,115
Due To Related Parties, Consolidated Funds	(257)		615
Accounts payable, accrued expenses and other liabilities	75		(184)
Net Cash Provided by (Used in) Operating Activities	299,644		(156,655)
Cash flows from investing activities:
Purchases of other investments	(38,658)		(15,899)
Purchase of business	0		(48,581)
Proceeds from sales of other investments	29,784		18,103
Purchase of fixed assets and intangibles	(11,558)		(7,862)
Net Cash Provided by (Used in) Investing Activities	(20,432)		(54,239)
Cash flows from financing activities:
Repayments on convertible debt	0		(20,860)
Payments of Debt Issuance Costs	1,700		1,480
Borrowings on notes and other debt	134,810		84,640
Repayments on notes and other debt	(95,458)		(2,740)
Purchase of treasury stock	$ (43,442)		$ (10,153)
Cash dividends paid	$ (3,433)		$ 0
Preferred dividends paid	$ (5,094)		$ (5,094)
Contingent liability payment	(5,653)		(1,235)
Capital contributions by non-controlling interests in operating entities	7,276		11,110
Capital withdrawals to non-controlling interests in operating entities	(4,330)		(1,713)
Consolidated Funds
Capital contributions by non-controlling interests in Consolidated Funds	339,966		213,723
Capital withdrawals to non-controlling interests in Consolidated Funds	(227,617)		(89,032)
Net Cash Provided by (Used in) Financing Activities	95,325		177,166
Change in cash and cash equivalents	374,537		(33,728)
Total cash beginning of period	415,014		442,113
Cash and cash equivalents	539,733	[1]	260,994
Cash collateral pledged	110,666		18,609
Segregated cash	139,152		128,782
Total cash at end of period	789,551		408,385
Supplemental information
Cash paid during the year for interest	116,457		98,363
Cash paid during the year for taxes	1,984		3,815
Purchase of treasury stock, at cost, through net settlement	6,296		22,420
Other Preferred Stock Dividends and Adjustments	5,094		5,094
Net assets (liabilities) acquired upon acquisition (net of cash)			90,727
Initial recognition of right of use asset			103,694
Initial recognition of lease liability			110,505
Noncash transfer of net assets from Unconsolidated Master Fund to Consolidated Fund			97,655
Decrease in noncontrolling interest due to deconsolidation of entity	360,711
Increase in noncontrolling interest due to consolidation of entity	48,596
Common stock issuance upon close of acquisition	$ 926		$ 14,446

[1] As of September 30, 2020, cash and cash equivalents include Level 1 cash in the amount of $479.7 million and Level 2 certificates of deposit of $60.0 million.