Condensed Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Preferred Class A	Common Stock Class A common stock	Common Stock Class C common stock	Additional Paid-in-Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Non-Controlling interest AOG	Non-Controlling interest Consolidated Funds
Balance at Dec. 31, 2018	$ 1,394,341	$ 298,761	$ 1,016		$ 326,007	$ (29,336)	$ (8,524)	$ 302,780	$ 503,637
Increase (Decrease) in Stockholders' Equity
Relinquished with deconsolidation of funds	(55)								(55)
Changes in ownership interests and related tax benefits	(18,397)		15		(6,339)			(12,073)
Capital contributions	55,911							1,876	54,035
Dividends/Distributions	(101,640)	(5,425)				(35,367)		(40,112)	(20,736)
Net income (loss)	121,576	5,425				39,524		59,003	17,624
Currency translation adjustment	1,084						1,284	1,459	(1,659)
Equity compensation	27,004				12,637			14,367
Equity compensation at Mar. 31, 2019	1,479,824	298,761	1,031		332,305	(25,179)	(7,240)	327,300	552,846
Increase (Decrease) in Stockholders' Equity
Changes in ownership interests and related tax benefits	(11,508)		5		(32,128)			20,615
Repurchases of Class A common stock	(10,449)		(4)		(10,445)
Capital contributions	61,464								61,464
Dividends/Distributions	(92,529)	(5,425)				(36,782)		(40,103)	(10,219)
Net income (loss)	74,878	5,425				26,714		34,393	8,346
Currency translation adjustment	(1,991)						(1,639)	(1,858)	1,506
Equity compensation	23,841				11,306			12,535
Stock option exercises	78,794		43		78,751
Equity compensation at Jun. 30, 2019	1,602,324	298,761	1,075		379,789	(35,247)	(8,879)	352,882	613,943
Increase (Decrease) in Stockholders' Equity
Changes in ownership interests and related tax benefits	1,209		1		(94,004)			95,212
Capital contributions	256,096		70		206,635				49,391
Dividends/Distributions	(125,982)	(5,425)				(36,967)		(48,970)	(34,620)
Net income (loss)	91,875	5,425				27,906		42,636	15,908
Currency translation adjustment	(9,429)						(2,131)	(2,352)	(4,946)
Equity compensation	22,393				10,816			11,577
Stock option exercises	4,296		1		4,295
Equity compensation at Sep. 30, 2019	1,842,782	298,761	1,147		507,531	(44,308)	(11,010)	450,985	639,676
Increase (Decrease) in Stockholders' Equity
Changes in ownership interests and related tax benefits	83		1		(1,505)			1,587
Capital contributions	7,961								7,961
Dividends/Distributions	(121,498)	(5,425)				(39,552)		(45,814)	(30,707)
Net income (loss)	84,475	5,425				33,040		48,184	(2,174)
Currency translation adjustment	13,658						4,963	5,431	3,264
Equity compensation	23,716				11,801			11,915
Stock option exercises	7,421		4		7,417
Equity compensation at Dec. 31, 2019	1,858,598	298,761	1,152	$ 0	525,244	(50,820)	(6,047)	472,288	618,020
Increase (Decrease) in Stockholders' Equity
Consolidation and deconsolidation of funds, net	(3,882)								(3,882)
Changes in ownership interests and related tax benefits	(74,079)		40		(196,670)			122,551
Issuances of common stock	383,334		121	1,152	382,061
Capital contributions	175,277							42,012	133,265
Dividends/Distributions	(125,755)	(5,425)				(51,090)		(55,748)	(13,492)
Net income (loss)	(275,797)	5,425				(36,461)		(78,355)	(166,406)
Currency translation adjustment	(14,208)						(4,802)	(4,719)	(4,687)
Equity compensation	32,557				16,420			16,137
Stock option exercises	19,551		11		19,540
Equity compensation at Mar. 31, 2020	$ 1,975,596	$ 298,761	$ 1,324	$ 1,152	$ 746,595	$ (138,371)	$ (10,849)	$ 514,166	$ 562,818