INVESTMENTS - Fair Value (Details) $ in Thousands	Mar. 31, 2023 USD ($) investment	Dec. 31, 2022 USD ($) investment
Schedule Of Investments In Marketable Securities [Line Items]
Investments, percentage of net assets, threshold percentage	5.00%	5.00%
Consolidated Funds
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 2,425,170	$ 2,098,838
Debt securities, fair value as a percentage of investments of consolidated funds	57.60%	53.70%
Equity securities, fair value	$ 1,700,103	$ 1,735,304
Equity securities, fair value as a percentage of investments of consolidated funds	40.30%	44.40%
Real estate investments, at fair value	$ 85,305	$ 74,471
Real estate, fair value as a percentage of investments of consolidated funds	2.10%	1.90%
Investments, at fair value	$ 4,210,578	$ 3,908,613
Total investments, fair value as a percentage of investments of consolidated funds	100.00%	100.00%
Consolidated Funds | Health care
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, fair value as a percentage of investments of consolidated funds	0.00%
Consolidated Funds | United States:
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 1,622,539	$ 1,318,317
Debt securities, fair value as a percentage of investments of consolidated funds	38.50%	33.70%
Total debt securities, cost	$ 1,746,319	$ 1,437,262
Equity securities, fair value	$ 1,294,314	$ 1,310,735
Equity securities, fair value as a percentage of investments of consolidated funds	30.70%	33.50%
Total equity securities, cost	$ 1,022,980	$ 1,000,922
Real estate investments, at fair value	$ 3,103	$ 1,796
Real estate, fair value as a percentage of investments of consolidated funds	0.10%	0.00%
Real estate securities, cost	$ 3,014	$ 1,797
Investments, fair value that exceeds threshold | investment	0	0
Consolidated Funds | United States: | Communication services
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 67,981	$ 100,995
Debt securities, fair value as a percentage of investments of consolidated funds	1.60%	2.60%
Equity securities, fair value	$ 68,814	$ 64,621
Equity securities, fair value as a percentage of investments of consolidated funds	1.60%	1.70%
Consolidated Funds | United States: | Consumer discretionary
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 129,065	$ 127,170
Debt securities, fair value as a percentage of investments of consolidated funds	3.10%	3.30%
Equity securities, fair value	$ 133,902	$ 133,104
Equity securities, fair value as a percentage of investments of consolidated funds	3.20%	3.40%
Consolidated Funds | United States: | Consumer staples
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 22,127	$ 23,542
Debt securities, fair value as a percentage of investments of consolidated funds	0.50%	0.60%
Consolidated Funds | United States: | Energy
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 174,682	$ 79,573
Debt securities, fair value as a percentage of investments of consolidated funds	4.10%	2.00%
Equity securities, fair value	$ 454,797	$ 482,984
Equity securities, fair value as a percentage of investments of consolidated funds	10.80%	12.40%
Consolidated Funds | United States: | Financials
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 300,523	$ 217,878
Debt securities, fair value as a percentage of investments of consolidated funds	7.10%	5.60%
Equity securities, fair value	$ 179,256	$ 181,980
Equity securities, fair value as a percentage of investments of consolidated funds	4.30%	4.70%
Real estate investments, at fair value	$ 0	$ 0
Real estate, fair value as a percentage of investments of consolidated funds	0.00%	0.00%
Consolidated Funds | United States: | Health care
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 113,307	$ 111,005
Debt securities, fair value as a percentage of investments of consolidated funds	2.70%	2.80%
Equity securities, fair value	$ 26,120	$ 26,191
Equity securities, fair value as a percentage of investments of consolidated funds	0.60%	0.70%
Consolidated Funds | United States: | Industrials
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 223,450	$ 206,479
Debt securities, fair value as a percentage of investments of consolidated funds	5.30%	5.30%
Equity securities, fair value	$ 322,192	$ 308,514
Equity securities, fair value as a percentage of investments of consolidated funds	7.70%	7.90%
Consolidated Funds | United States: | Information technology
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 107,790	$ 136,714
Debt securities, fair value as a percentage of investments of consolidated funds	2.60%	3.50%
Equity securities, fair value	$ 14,702	$ 14,107
Equity securities, fair value as a percentage of investments of consolidated funds	0.30%	0.40%
Consolidated Funds | United States: | Materials
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 111,986	$ 118,578
Debt securities, fair value as a percentage of investments of consolidated funds	2.70%	3.00%
Equity securities, fair value	$ 899	$ 899
Equity securities, fair value as a percentage of investments of consolidated funds	0.00%	0.00%
Consolidated Funds | United States: | Real estate
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 162,536	$ 182,643
Debt securities, fair value as a percentage of investments of consolidated funds	3.90%	4.70%
Real estate investments, at fair value	$ 3,103	$ 1,796
Real estate, fair value as a percentage of investments of consolidated funds	0.10%	0.00%
Consolidated Funds | United States: | Utilities
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 11,384	$ 11,850
Debt securities, fair value as a percentage of investments of consolidated funds	0.30%	0.30%
Equity securities, fair value	$ 93,632	$ 98,335
Equity securities, fair value as a percentage of investments of consolidated funds	2.20%	2.50%
Consolidated Funds | United States: | Other
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 197,708	$ 1,890
Debt securities, fair value as a percentage of investments of consolidated funds	4.70%	0.00%
Consolidated Funds | Europe:
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 225,766	$ 217,816
Debt securities, fair value as a percentage of investments of consolidated funds	5.40%	5.60%
Total debt securities, cost	$ 229,088	$ 230,090
Equity securities, fair value	$ 281,591	$ 266,272
Equity securities, fair value as a percentage of investments of consolidated funds	6.80%	6.80%
Total equity securities, cost	$ 250,259	$ 241,129
Real estate investments, at fair value	$ 82,202	$ 72,675
Real estate, fair value as a percentage of investments of consolidated funds	2.00%	1.90%
Real estate securities, cost	$ 75,167	$ 69,100
Consolidated Funds | Europe: | Communication services
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 109,740	$ 103,068
Debt securities, fair value as a percentage of investments of consolidated funds	2.60%	2.70%
Consolidated Funds | Europe: | Consumer discretionary
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 19,398	$ 13,997
Debt securities, fair value as a percentage of investments of consolidated funds	0.50%	0.40%
Equity securities, fair value	$ 134,031	$ 130,868
Equity securities, fair value as a percentage of investments of consolidated funds	3.20%	3.30%
Consolidated Funds | Europe: | Consumer staples
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 8,355	$ 8,024
Debt securities, fair value as a percentage of investments of consolidated funds	0.20%	0.20%
Consolidated Funds | Europe: | Energy
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 1,539	$ 1,097
Debt securities, fair value as a percentage of investments of consolidated funds	0.00%	0.00%
Consolidated Funds | Europe: | Financials
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 27,865	$ 35,091
Debt securities, fair value as a percentage of investments of consolidated funds	0.70%	0.90%
Equity securities, fair value	$ 33,189	$ 31,701
Equity securities, fair value as a percentage of investments of consolidated funds	0.80%	0.80%
Consolidated Funds | Europe: | Health care
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 7,009	$ 8,178
Debt securities, fair value as a percentage of investments of consolidated funds	0.20%	0.20%
Consolidated Funds | Europe: | Health care | Equity securities
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, fair value	$ 3	$ 9
Equity securities, fair value as a percentage of investments of consolidated funds		0.00%
Consolidated Funds | Europe: | Industrials
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 14,547	$ 12,384
Debt securities, fair value as a percentage of investments of consolidated funds	0.30%	0.30%
Equity securities, fair value	$ 56,893	$ 53,790
Equity securities, fair value as a percentage of investments of consolidated funds	1.40%	1.40%
Consolidated Funds | Europe: | Information technology
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 4,167	$ 4,583
Debt securities, fair value as a percentage of investments of consolidated funds	0.10%	0.10%
Consolidated Funds | Europe: | Materials
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 11,028	$ 10,920
Debt securities, fair value as a percentage of investments of consolidated funds	0.30%	0.30%
Equity securities, fair value	$ 24,282	$ 24,282
Equity securities, fair value as a percentage of investments of consolidated funds	0.60%	0.60%
Consolidated Funds | Europe: | Real estate
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 14,385	$ 12,888
Debt securities, fair value as a percentage of investments of consolidated funds	0.30%	0.30%
Equity securities, fair value	$ 33,193	$ 25,622
Equity securities, fair value as a percentage of investments of consolidated funds	0.80%	0.70%
Real estate investments, at fair value	$ 82,202	$ 72,675
Real estate, fair value as a percentage of investments of consolidated funds	2.00%	1.90%
Consolidated Funds | Europe: | Utilities
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 5,220	$ 5,102
Debt securities, fair value as a percentage of investments of consolidated funds	0.10%	0.10%
Consolidated Funds | Europe: | Other
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 2,513	$ 2,484
Debt securities, fair value as a percentage of investments of consolidated funds	0.10%	0.10%
Consolidated Funds | Asia and other:
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 576,865	$ 562,705
Debt securities, fair value as a percentage of investments of consolidated funds	13.90%	14.40%
Total debt securities, cost	$ 602,056	$ 581,467
Equity securities, fair value	$ 124,198	$ 158,297
Equity securities, fair value as a percentage of investments of consolidated funds	2.80%	4.00%
Total equity securities, cost	$ 712,835	$ 722,128
Consolidated Funds | Asia and other: | Communication services
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 3,075	$ 5,419
Debt securities, fair value as a percentage of investments of consolidated funds	0.10%	0.10%
Consolidated Funds | Asia and other: | Consumer discretionary
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 4,347	$ 5,641
Debt securities, fair value as a percentage of investments of consolidated funds	0.10%	0.10%
Consolidated Funds | Asia and other: | Consumer staples
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 19,399	$ 19,125
Debt securities, fair value as a percentage of investments of consolidated funds	0.50%	0.50%
Consolidated Funds | Asia and other: | Energy
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 12,598	$ 9,163
Debt securities, fair value as a percentage of investments of consolidated funds	0.30%	0.20%
Equity securities, fair value	$ 5,867	$ 7,581
Equity securities, fair value as a percentage of investments of consolidated funds	0.10%	0.20%
Consolidated Funds | Asia and other: | Financials
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 7,159	$ 8,344
Debt securities, fair value as a percentage of investments of consolidated funds	0.20%	0.20%
Consolidated Funds | Asia and other: | Health care
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 2,899	$ 2,837
Debt securities, fair value as a percentage of investments of consolidated funds	0.10%	0.10%
Consolidated Funds | Asia and other: | Industrials
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 3,650	$ 3,754
Debt securities, fair value as a percentage of investments of consolidated funds	0.10%	0.10%
Equity securities, fair value	$ 80,885	$ 113,270
Equity securities, fair value as a percentage of investments of consolidated funds	1.90%	2.90%
Consolidated Funds | Asia and other: | Information technology
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 1,067	$ 695
Debt securities, fair value as a percentage of investments of consolidated funds	0.00%	0.00%
Consolidated Funds | Asia and other: | Materials
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 113,278	$ 113,784
Debt securities, fair value as a percentage of investments of consolidated funds	2.70%	2.90%
Consolidated Funds | Asia and other: | Real estate
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 403,630	$ 328,343
Debt securities, fair value as a percentage of investments of consolidated funds	9.60%	8.40%
Equity securities, fair value	$ 32,916	$ 32,916
Equity securities, fair value as a percentage of investments of consolidated funds	0.80%	0.80%
Consolidated Funds | Asia and other: | Utilities
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 4,324	$ 5,602
Debt securities, fair value as a percentage of investments of consolidated funds	0.10%	0.10%
Equity securities, fair value	$ 4,530	$ 4,530
Equity securities, fair value as a percentage of investments of consolidated funds	0.10%	0.10%
Consolidated Funds | Asia and other: | Other
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities, fair value	$ 1,439	$ 59,998
Debt securities, fair value as a percentage of investments of consolidated funds	0.00%	1.50%