Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities
Net income (loss)	$ 107,111	$ 88,903
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Bad debt expense	1,208	431
Depreciation and amortization	2,155	1,679
(Income) loss from equity method investments	(3,114)	(1,774)
Equity-based compensation	58,335	49,729
Deferred tax provision	8,568	8,116
Gain on equity method investment		(17,450)
Other	3,688	3,027
Changes in assets and liabilities:
Accounts receivable	(8,475)	(5,067)
Other receivables	(54,549)	(2,498)
Prepaid expenses and other assets	933	(6,497)
Deferred compensation	(1,160)	(535)
Compensation payable	(32,227)	(47,168)
Accounts payable and accrued expenses	(12,012)	(9,677)
Deferred revenue	(998)	(86)
Dividends received	2,737	11,672
Other liabilities	(2,205)	(182)
Net cash provided by (used in) operating activities	69,995	72,623
Cash flows from investing activities
Purchase of investments	(55,479)	(98,319)
Proceeds from sales of investments	92,310	53,000
Note payments received from employees	193	403
Notes issued to employees		(400)
Purchase of equipment and leasehold improvements	(3,133)	(3,013)
Net cash provided by (used in) investing activities	33,891	(48,329)
Cash flows from financing activities
Dividends and distributions	(167,145)	(155,304)
Payments under tax receivable agreement		(5,032)
Proceeds from exercise of stock options	6,695	4,650
Payments to settle employee tax obligations on share-based awards	(24,172)	(9,266)
Class A partnership units and other equity purchased	(135)	(101)
Net cash provided by (used in) financing activities	(184,757)	(165,053)
Effect of exchange rate fluctuations on cash, cash equivalents, and restricted cash	401	1,682
Net increase (decrease) in cash, cash equivalents, and restricted cash	(80,470)	(139,077)
Cash, cash equivalents, and restricted cash, beginning of period	213,894	319,585
Cash, cash equivalents, and restricted cash, end of period	133,424	180,508
Cash paid during the period for:
Income taxes	14,185	20,352
Dividends paid, declared in the prior year		68,066
Other non-cash activity
Dividend equivalents issued	24,767	17,176
Dividend declared not paid		55,900
Class A Partnership Units or other equity converted into Class A Common Stock	22,174	23,557
Cumulative Effect Adjustment upon Adoption of ASU		658
Cumulative Effect Adjustment upon Adoption of ASU	3,155
Exercised stock option proceeds receivable	24	647
Forfeiture of fully-vested Group LP units or other equity units	$ 677	$ 36