INVESTMENTS - Fair Value (Details) - Consolidated Funds - USD ($) $ in Thousands | Mar. 31, 2021 | Dec. 31, 2020 |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 7,850,941 | $ 7,578,788 |
Debt securities, fair value as a percentage of investments of consolidated funds | 93.70% | 97.20% |
Equity securities, fair value | $ 528,889 | $ 213,642 |
Equity securities, fair value as a percentage of investments of consolidated funds | 6.30% | 2.70% |
Real estate investments, at fair value | $ 0 | $ 6,879 |
Real estate, fair value as a percentage of investments of consolidated funds | 0.00% | 0.10% |
Investments, at fair value | $ 8,379,830 | $ 7,799,309 |
Total investments, fair value as a percentage of investments of consolidated funds | 100.00% | 100.00% |
Debt securities: | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 4,280,563 | $ 4,043,650 |
Debt securities, fair value as a percentage of investments of consolidated funds | 50.90% | 51.90% |
Total debt securities, cost | $ 4,291,934 | $ 4,064,289 |
Equity securities, fair value | $ 469,786 | $ 210,725 |
Equity securities, fair value as a percentage of investments of consolidated funds | 5.60% | 2.70% |
Real estate investments, at fair value | $ 0 | $ 6,879 |
Real estate, fair value as a percentage of investments of consolidated funds | 0.00% | 0.10% |
Real estate securities, cost | $ 0 | $ 6,760 |
Total equity securities, cost | 498,462 | 282,682 |
Debt securities: | Communication services | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 556,783 | $ 554,779 |
Debt securities, fair value as a percentage of investments of consolidated funds | 6.60% | 7.10% |
Equity securities, fair value | $ 36,340 | $ 16,822 |
Equity securities, fair value as a percentage of investments of consolidated funds | 0.40% | 0.20% |
Debt securities: | Consumer discretionary | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 573,247 | $ 568,195 |
Debt securities, fair value as a percentage of investments of consolidated funds | 6.80% | 7.30% |
Equity securities, fair value | $ 101,104 | $ 604 |
Equity securities, fair value as a percentage of investments of consolidated funds | 1.20% | 0.00% |
Debt securities: | Consumer staples | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 150,696 | $ 118,641 |
Debt securities, fair value as a percentage of investments of consolidated funds | 1.80% | 1.50% |
Debt securities: | Energy | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 210,012 | $ 232,309 |
Debt securities, fair value as a percentage of investments of consolidated funds | 2.50% | 3.00% |
Equity securities, fair value | $ 130,492 | $ 21,747 |
Equity securities, fair value as a percentage of investments of consolidated funds | 1.60% | 0.30% |
Debt securities: | Financials | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 321,852 | $ 287,291 |
Debt securities, fair value as a percentage of investments of consolidated funds | 3.80% | 3.70% |
Equity securities, fair value | $ 84,865 | $ 85,715 |
Equity securities, fair value as a percentage of investments of consolidated funds | 1.00% | 1.10% |
Debt securities: | Health care | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 399,955 | $ 410,317 |
Debt securities, fair value as a percentage of investments of consolidated funds | 4.80% | 5.30% |
Debt securities: | Industrials | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 734,561 | $ 727,471 |
Debt securities, fair value as a percentage of investments of consolidated funds | 8.80% | 9.30% |
Equity securities, fair value | $ 39,891 | $ 8,752 |
Equity securities, fair value as a percentage of investments of consolidated funds | 0.50% | 0.10% |
Debt securities: | Information technology | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 539,981 | $ 504,442 |
Debt securities, fair value as a percentage of investments of consolidated funds | 6.40% | 6.50% |
Debt securities: | Materials | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 260,273 | $ 251,978 |
Debt securities, fair value as a percentage of investments of consolidated funds | 3.10% | 3.20% |
Debt securities: | Real estate | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 225,055 | $ 111,622 |
Debt securities, fair value as a percentage of investments of consolidated funds | 2.70% | 1.40% |
Real estate investments, at fair value | $ 0 | $ 6,879 |
Real estate, fair value as a percentage of investments of consolidated funds | 0.00% | 0.10% |
Debt securities: | Utilities | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 271,181 | $ 264,758 |
Debt securities, fair value as a percentage of investments of consolidated funds | 3.20% | 3.40% |
Equity securities, fair value | $ 77,094 | $ 77,085 |
Equity securities, fair value as a percentage of investments of consolidated funds | 0.90% | 1.00% |
Debt securities: | Other | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 36,967 | $ 11,847 |
Debt securities, fair value as a percentage of investments of consolidated funds | 0.40% | 0.20% |
Europe: | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 3,252,318 | $ 3,246,342 |
Debt securities, fair value as a percentage of investments of consolidated funds | 38.80% | 41.60% |
Total debt securities, cost | $ 3,247,678 | $ 3,233,125 |
Equity securities, fair value | $ 5,223 | $ 2,917 |
Equity securities, fair value as a percentage of investments of consolidated funds | 0.00% | 0.00% |
Total equity securities, cost | $ 5,391 | $ 2,919 |
Europe: | Communication services | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 483,940 | $ 471,595 |
Debt securities, fair value as a percentage of investments of consolidated funds | 5.80% | 6.00% |
Europe: | Consumer discretionary | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 761,434 | $ 755,084 |
Debt securities, fair value as a percentage of investments of consolidated funds | 9.10% | 9.70% |
Equity securities, fair value | $ 1,467 | $ 0 |
Equity securities, fair value as a percentage of investments of consolidated funds | 0.00% | 0.00% |
Europe: | Consumer staples | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 208,950 | $ 219,934 |
Debt securities, fair value as a percentage of investments of consolidated funds | 2.50% | 2.80% |
Europe: | Energy | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 2,082 | $ 8,033 |
Debt securities, fair value as a percentage of investments of consolidated funds | 0.00% | 0.10% |
Europe: | Financials | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 74,653 | $ 75,988 |
Debt securities, fair value as a percentage of investments of consolidated funds | 0.90% | 1.00% |
Equity securities, fair value | $ 3,756 | $ 2,917 |
Equity securities, fair value as a percentage of investments of consolidated funds | 0.00% | 0.00% |
Europe: | Health care | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 607,110 | $ 629,210 |
Debt securities, fair value as a percentage of investments of consolidated funds | 7.20% | 8.10% |
Europe: | Industrials | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 479,205 | $ 487,243 |
Debt securities, fair value as a percentage of investments of consolidated funds | 5.70% | 6.20% |
Europe: | Information technology | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 268,450 | $ 255,662 |
Debt securities, fair value as a percentage of investments of consolidated funds | 3.20% | 3.30% |
Europe: | Materials | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 315,740 | $ 303,468 |
Debt securities, fair value as a percentage of investments of consolidated funds | 3.80% | 3.90% |
Europe: | Real estate | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 32,965 | $ 26,100 |
Debt securities, fair value as a percentage of investments of consolidated funds | 0.40% | 0.30% |
Europe: | Utilities | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 6,002 | $ 9,397 |
Debt securities, fair value as a percentage of investments of consolidated funds | 0.10% | 0.10% |
Europe: | Other | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 11,787 | $ 4,628 |
Debt securities, fair value as a percentage of investments of consolidated funds | 0.10% | 0.10% |
Asia and other: | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 318,060 | $ 288,796 |
Debt securities, fair value as a percentage of investments of consolidated funds | 3.60% | 3.70% |
Total debt securities, cost | $ 314,643 | $ 288,452 |
Equity securities, fair value | $ 53,880 | $ 0 |
Equity securities, fair value as a percentage of investments of consolidated funds | 0.60% | 0.00% |
Total equity securities, cost | $ 52,364 | $ 0 |
Asia and other: | Communication services | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 9,652 | $ 18,741 |
Debt securities, fair value as a percentage of investments of consolidated funds | 0.10% | 0.20% |
Asia and other: | Consumer discretionary | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 36,362 | $ 35,580 |
Debt securities, fair value as a percentage of investments of consolidated funds | 0.40% | 0.50% |
Asia and other: | Consumer staples | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 27,816 | $ 23,755 |
Debt securities, fair value as a percentage of investments of consolidated funds | 0.30% | 0.30% |
Asia and other: | Energy | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 20,484 | $ 9,247 |
Debt securities, fair value as a percentage of investments of consolidated funds | 0.20% | 0.10% |
Equity securities, fair value | $ 5,850 | $ 0 |
Equity securities, fair value as a percentage of investments of consolidated funds | 0.10% | 0.00% |
Asia and other: | Financials | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 8,217 | $ 12,335 |
Debt securities, fair value as a percentage of investments of consolidated funds | 0.10% | 0.20% |
Asia and other: | Health care | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 1,344 | $ 1,084 |
Debt securities, fair value as a percentage of investments of consolidated funds | 0.00% | 0.00% |
Asia and other: | Industrials | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 9,345 | $ 4,759 |
Debt securities, fair value as a percentage of investments of consolidated funds | 0.10% | 0.10% |
Equity securities, fair value | $ 11,457 | $ 0 |
Equity securities, fair value as a percentage of investments of consolidated funds | 0.10% | 0.00% |
Asia and other: | Information technology | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 1,633 | $ 3,631 |
Debt securities, fair value as a percentage of investments of consolidated funds | 0.00% | 0.00% |
Asia and other: | Materials | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 75,852 | $ 68,791 |
Debt securities, fair value as a percentage of investments of consolidated funds | 0.90% | 0.90% |
Asia and other: | Real estate | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 117,424 | $ 75,187 |
Debt securities, fair value as a percentage of investments of consolidated funds | 1.40% | 1.00% |
Equity securities, fair value | $ 36,573 | $ 0 |
Equity securities, fair value as a percentage of investments of consolidated funds | 0.40% | 0.00% |
Asia and other: | Utilities | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 6,584 | $ 9,619 |
Debt securities, fair value as a percentage of investments of consolidated funds | 0.10% | 0.10% |
Asia and other: | Other | | |
Schedule Of Investments In Marketable Securities [Line Items] | | |
Debt securities, fair value | $ 3,347 | $ 26,067 |
Debt securities, fair value as a percentage of investments of consolidated funds | 0.00% | 0.30% |