INVESTMENTS (Tables)

12 Months Ended

Dec. 31, 2017

Investments in and Advances to Affiliates, Schedule of Investments [Abstract]

Summary of investments held

Investments held in the Consolidated Funds are summarized below:

	Fair value at				Fair value as a percentage of total investments at
	December 31,		December 31,		December 31,		December 31,
	2017		2016		2017		2016
United States:
Fixed income securities:
Consumer discretionary	$	1,295,732	$	665,773	23.2	%	20.0	%
Consumer staples	55,073		64,840		1.0	%	1.9	%
Energy	176,836		45,409		3.2	%	1.4	%
Financials	270,520		139,285		4.8	%	4.2	%
Healthcare, education and childcare	449,888		246,403		8.1	%	7.4	%
Industrials	370,926		149,632		6.6	%	4.5	%
Information technology	167,089		194,394		3.0	%	5.8	%
Materials	185,170		139,994		3.3	%	4.2	%
Telecommunication services	399,617		261,771		7.2	%	7.9	%
Utilities	77,102		47,800		1.4	%	1.4	%
Total fixed income securities (cost: $3,459,318 and $1,945,977 at December 31, 2017 and 2016, respectively)	3,447,953		1,955,301		61.8	%	58.7	%
Equity securities:
Energy	126		421		0.0	%	0.0	%
Total equity securities (cost: $2,265 and $2,872 at December 31, 2017 and 2016, respectively)	126		421		0.0	%	0.0	%
Partnership interests:
Partnership interests	232,332		171,696		4.2	%	5.2	%
Total partnership interests (cost: $190,000 and $147,000 at December 31, 2017 and 2016, respectively)	232,332		171,696		4.2	%	5.2	%

	Fair value at				Fair value as a percentage of total investments at
	December 31,		December 31,		December 31,		December 31,
	2017		2016		2017		2016
Europe:
Fixed income securities:
Consumer discretionary	$	604,608	$	274,678	10.8	%	8.2	%
Energy	2,413		—		0.0	%	—	%
Consumer staples	76,361		39,197		1.4	%	1.2	%
Financials	81,987		28,769		1.5	%	0.9	%
Healthcare, education and childcare	209,569		111,589		3.8	%	3.4	%
Industrials	145,706		118,466		2.6	%	3.6	%
Information technology	21,307		49,507		0.4	%	1.5	%
Materials	213,395		124,629		3.8	%	3.7	%
Telecommunication services	182,543		118,632		3.3	%	3.6	%
Utilities	—		4,007		—	%	0.1	%
Total fixed income securities (cost: $1,545,297 and $892,108 at December 31, 2017 and 2016, respectively)	1,537,889		869,474		27.6	%	26.2	%
Equity securities:
Consumer staples	—		1,517		—	%	0.0	%
Healthcare, education and childcare	63,155		41,329		1.1	%	1.2	%
Telecommunication services	—		24		—	%	0.0	%
Total equity securities (cost: $67,198 and $67,290 at December 31, 2017 and 2016, respectively)	63,155		42,870		1.1	%	1.2	%
Asia and other:
Fixed income securities:
Consumer discretionary	2,008		24,244		0.0	%	0.7	%
Financials	12,453		1,238		0.2	%	0.0	%
Healthcare, education and childcare	—		10,010		—	%	0.3	%
Telecommunication services	21,848		8,696		0.4	%	0.3	%
Total fixed income securities (cost: $36,180 and $46,545 at December 31, 2017 and 2016, respectively)	36,309		44,188		0.6	%	1.3	%
Equity securities:
Consumer discretionary	59,630		44,642		1.1	%	1.3	%
Consumer staples	45,098		50,101		0.8	%	1.5	%
Healthcare, education and childcare	44,637		32,598		0.8	%	1.0	%
Industrials	16,578		16,578		0.3	%	0.5	%
Total equity securities (cost: $122,418 and $122,418 at December 31, 2017 and 2016, respectively)	165,943		143,919		3.0	%	4.3	%

	Fair value at				Fair value as a percentage of total investments at
	December 31,		December 31,		December 31,		December 31,
	2017		2016		2017		2016
Canada:
Fixed income securities:
Consumer discretionary	$	6,757	$	—	0.1	%	$	—
Consumer staples	15,351		5,256		0.3	%	0.2		%
Energy	33,715		12,830		0.6	%	0.4		%
Healthcare, education and childcare	—		15,509		—	%	0.5		%
Industrials	18,785		1,401		0.3	%	0.0		%
Telecommunication services	6,189		13,852		0.1	%	0.4		%
Total fixed income securities (cost: $80,201 and $48,274 at December 31, 2017 and 2016, respectively)	80,797		48,848		1.4	%	1.5		%
Equity securities:
Consumer discretionary	5,912		164		0.1	%	0.0		%
Total equity securities (cost: $17,202 and $408 at December 31, 2017 and 2016, respectively)	5,912		164		0.1	%	0.0		%
Australia:
Fixed income securities:
Consumer discretionary	10,863		5,627		0.2	%	0.2		%
Energy	1,563		6,046		0.0	%	0.2		%
Industrials	—		2,926		—	%	0.1		%
Utilities	—		21,154		—	%	0.6		%
Total fixed income securities (cost: $12,714 and $37,975 at December 31, 2017 and 2016, respectively)	12,426		35,753		0.2	%	1.1		%
Equity Securities:
Utilities	—		17,569		—	%	0.5		%
Total equity securities (cost: $0 and $18,442 at December 31, 2017 and 2016, respectively)	—		17,569		—	%	0.5		%
Total fixed income securities	5,115,374		2,953,564		91.6	%	88.8		%
Total equity securities	235,136		204,943		4.2	%	6.0		%
Total partnership interests	232,332		171,696		4.2	%	5.2		%
Total investments, at fair value	$	5,582,842	$	3,330,203

					Percentage of total investments
	December 31,				December 31,
	2017		2016		2017		2016
Private Investment Partnership Interests:
Equity method private investment partnership interests(1)	$	369,774	$	309,512	57.1	%	68.5	%
Other private investment partnership interests, at fair value	80,767		53,229		12.5	%	11.8	%
Total private investment partnership interests	450,541		362,741		69.6	%	80.3	%
Collateralized Loan Obligations:
Collateralized loan obligations, at fair value	195,158		89,111		30.1	%	19.7	%
Common Stock:
Common stock, at fair value	1,636		100		0.3	%	0.0	%
Total investments	$	647,335	$	451,952

(1) Investment or portion of the investment is denominated in foreign currency and is translated into U.S. dollars at each reporting date.

Schedule of equity method investments

The following tables present summarized financial information for the Company's equity method investments for the years ended December 31, 2017, 2016 and 2015.

	As of December 31, 2017 and the Year then Ended
	Credit			Private Equity			Real Estate			Total
Statement of Financial Condition(1)
Investments	$	5,903,009		$	9,849,829		$	2,997,789		$	18,750,627
Total assets	6,435,364			10,033,790			3,174,149			19,643,303
Total liabilities	665,680			519,349			202,174			1,387,203
Total equity	5,769,684			9,514,441			2,971,975			18,256,100
Statement of Operations(1)
Revenues	$	603,682		$	144,829		$	154,967		$	903,478
Expenses	(169,086		)	(91,803		)	(67,396		)	(328,285		)
Net realized and unrealized gain from investments	41,185			2,335,027			365,091			2,741,303
Income tax expense	(2,700		)	(31,359		)	(13,092		)	(47,151		)
Net income	$	473,081		$	2,356,694		$	439,570		$	3,269,345

	As of December 31, 2016 and the Year then Ended
	Credit			Private Equity			Real Estate			Total
Statement of Financial Condition(1)
Investments	$	4,365,460		$	8,857,500		$	2,477,523		$	15,700,483
Total assets	4,884,680			9,143,070			2,625,264			16,653,014
Total liabilities	522,443			197,380			510,252			1,230,075
Total equity	4,362,237			8,945,690			2,115,012			15,422,939
Statement of Operations(1)
Revenues	$	416,228		$	839,723		$	114,937		$	1,370,888
Expenses	(107,465		)	(134,573		)	(77,021		)	(319,059		)
Net realized and unrealized gain from investments	36,316			1,489,624			171,467			1,697,407
Income tax expense	(345		)	(27,587		)	(5,380		)	(33,312		)
Net income	$	344,734		$	2,167,187		$	204,003		$	2,715,924

(1) In prior year presentation, certain funds that are equity method investments were not included in the table above. Current year presentation has been recast to show this immaterial prior period disclosure.

	For the Year Ended December 31, 2015
	Credit			Private Equity			Real Estate			Total
Statement of Operations(1)
Revenues	$	313,833		$	350,444		$	95,340		$	759,617
Expenses	(60,389		)	(124,216		)	(65,340		)	(249,945		)
Net realized and unrealized gain from investments	(118,035		)	243,470			86,074			211,509
Income tax expense	(3,293		)	(22,004		)	(13,104		)	(38,401		)
Net income	$	132,116		$	447,694		$	102,970		$	682,780

(1) In prior year presentation, certain funds that are equity method investments were not included in the table above. Current year presentation has been recast to show this immaterial prior period disclosure.

Summary of cost and fair value of investments classified as HTM

A summary of the cost and fair value of CLO notes classified as held-to maturity investments is as follows:

	As of December 31,
	2017		2016
Amortized cost	$	—	$	16,519
Unrealized loss, net	—		(116		)
Fair value	$	—	$	16,403