Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net income (loss)	$ (35,156)	$ 30,050
Adjustments to reconcile net income (loss) to net cash provided by / (used in) operating activities:
Depreciation and amortization	6,480	4,283
Amortization of Debt Issue Costs	587	0
Amortization of debt discount	3,366	3,081
Tax benefits from share based payment arrangements	(744)	3,694
Share-based compensation	13,036	10,870
Deferred tax benefit	(13,982)	2,651
Deferred rent obligations	(402)	(1,453)
Net loss on disposal of fixed assets	0	31
Contingent liability adjustment	2,135	0
Purchases of securities owned, at fair value	(2,085,486)	(2,614,177)
Proceeds from sales of securities owned, at fair value	2,219,623	2,634,224
Proceeds from sales of securities sold, not yet purchased, at fair value	1,856,801	1,106,836
Payments to cover securities sold, not yet purchased, at fair value	(1,841,743)	(1,152,202)
Net (gains) losses on securities, derivatives and other investments	7,731	(54,401)
Consolidated Funds
Purchases of securities owned, at fair value	(22,056)	0
Proceeds from sales of securities owned, at fair value	1,517	0
Proceeds From Securities Sold Not Yet Purchased At Fair Value	2,226	0
Payments to Cover Securities Sold Not Yet Purchased at Fair Value	947	0
Purchases of other investments	(221,506)	(76,201)
Proceeds from sales of other investments	12,431	5,111
Net realized and unrealized (gains) losses on investments and other transactions	19,100	(6,975)
(Increase) decrease in operating assets:
Cash collateral pledged	(3,687)	(944)
Securities owned, at fair value, held at broker dealer	870	(1,357)
Receivable on derivative contracts, at fair value	14,647	(30,224)
Securities borrowed	0	676,100
Receivable from brokers	851	14,313
Fees receivable, net of allowance	(10,939)	(24,089)
Due from related parties	4,134	(1,406)
Other assets	(22,173)	(2,324)
Consolidated Funds
Cash and cash equivalents	5,992	(477)
Receivable on derivative contracts	(60)	0
Other assets	(584)	985
Increase (decrease) in operating liabilities:
Securities sold, not yet purchased, at fair value, held at broker dealer	(2,029)	(1,648)
Payable for derivative contracts, at fair value	(6,327)	25,766
Securities loaned	0	(682,493)
Payable to brokers	(122,493)	33,835
Compensation payable	(145,817)	(56,577)
Fees payable	(3,114)	382
Due to related parties	(65)	(115)
Accounts payable, accrued expenses and other liabilities	8,831	(5,458)
Consolidated Funds
Contributions received in advance	(850)	0
Payable to brokers	731	0
Due to related parties	264	0
Accounts payable, accrued expenses and other liabilities	198	122
Net cash provided by / (used in) operating activities	(358,609)	(160,187)
Cash flows from investing activities:
Purchases of other investments	(24,956)	(8,560)
Payments to Acquire Businesses, Net of Cash Acquired	6,258	0
Proceeds from sales of other investments	22,680	36,106
Proceeds from loans held for investments	40,400	0
Purchase of fixed assets	(14,694)	(1,426)
Net cash provided by / (used in) investing activities	17,172	26,120
Cash flows from financing activities:
Proceeds from Issuance of Preferred Stock, net of issuance costs	0	117,310
Capped call option transaction	0	15,879
Borrowings on notes and other debt	30,709	2,140
Repayments on notes and other debt	(1,901)	(1,836)
Income tax effect from share-based payment arrangements	(744)	3,694
Proceeds from Stock Options Exercised	0	395
Purchase of treasury stock	(6,014)	(22,569)
Cash paid to acquire net assets (contingent liability payable)	(3,493)	(1,725)
Capital contributions by redeemable non-controlling interests in operating entities	0	5,644
Capital withdrawals to redeemable non-controlling interests in operating entities	(5,144)	(5,723)
Consolidated Funds
Capital contributions by redeemable non-controlling interests in Consolidated Funds	231,871	71,202
Capital withdrawals to redeemable non-controlling interests in Consolidated Funds	(4,549)	(2,388)
Net cash provided by / (used in) financing activities	240,735	150,265
Change in cash and cash equivalents	(100,702)	16,198
Cash and cash equivalents at beginning of period	158,485	129,509
Cash and cash equivalents at end of period	57,783	145,707
Supplemental information
Purchase of treasury stock, at cost, through net settlement	8,562	8,520
Noncash or Part Noncash Acquisition, Net Nonmonetary Assets Acquired (Liabilities Assumed)	7,164	0
Preferred stock dividends declared	3,396	755
Net Assets of Deconsolidated Entity	$ 73,042	$ 0