INVESTMENTS - Investments, at Fair Value (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	$ 3,302,188	$ 45,179,906
Total investments, at fair value, Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	100.00%	100.00%
Debt securities:
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 3,129,426	$ 17,680,144
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	94.80%	39.20%
Equity securities:
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 172,762	$ 27,499,762
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	5.20%	60.80%
Total securities sold short, at fair value	$ (61,838)	$ (91,246)
United States: | Debt securities:
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 2,082,565	$ 13,008,057
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	63.20%	28.80%
United States: | Debt securities: | Consumer discretionary
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 550,122	$ 3,387,072
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	16.70%	7.50%
United States: | Debt securities: | Consumer staples
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 153,994	$ 686,071
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	4.70%	1.50%
United States: | Debt securities: | Energy
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 50,760	$ 854,220
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	1.50%	1.90%
United States: | Debt securities: | Financials
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 124,291	$ 1,293,508
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	3.80%	2.90%
United States: | Debt securities: | Government
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 0	$ 95,508
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	0.20%
United States: | Debt securities: | Health care
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 292,452	$ 1,135,799
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	8.90%	2.50%
United States: | Debt securities: | Industrials
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 352,038	$ 1,710,706
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	10.70%	3.80%
United States: | Debt securities: | Information technology
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 251,870	$ 1,293,815
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	7.60%	2.90%
United States: | Debt securities: | Materials
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 197,230	$ 1,393,521
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	6.00%	3.10%
United States: | Debt securities: | Telecommunication services
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 65,559	$ 471,711
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	2.00%	1.00%
United States: | Debt securities: | Utilities
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 44,249	$ 686,126
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	1.30%	1.50%
United States: | Equity securities:
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 3,764	$ 15,080,291
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.10%	33.30%
United States: | Equity securities: | Consumer discretionary
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 634	$ 1,813,832
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	4.00%
United States: | Equity securities: | Consumer staples
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 0	$ 872,472
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	1.90%
United States: | Equity securities: | Energy
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 0	$ 1,810,290
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	4.00%
United States: | Equity securities: | Financials
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 3,018	$ 7,639,790
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.10%	16.90%
United States: | Equity securities: | Health care
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 112	$ 92,866
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	0.20%
United States: | Equity securities: | Industrials
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 0	$ 1,728,086
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	3.80%
United States: | Equity securities: | Information technology
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 0	$ 67,253
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	0.20%
United States: | Equity securities: | Materials
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 0	$ 882,366
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	2.00%
United States: | Equity securities: | Telecommunication services
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 0	$ 16,471
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	0.00%
United States: | Equity securities: | Utilities
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 0	$ 156,865
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	0.30%
Europe: | Debt securities:
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 997,536	$ 3,709,217
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	30.10%	8.20%
Europe: | Debt securities: | Consumer discretionary
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 304,868	$ 1,329,387
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	9.20%	2.90%
Europe: | Debt securities: | Consumer staples
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 81,685	$ 222,789
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	2.50%	0.50%
Europe: | Debt securities: | Energy
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 13,712	$ 144,742
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.40%	0.30%
Europe: | Debt securities: | Financials
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 16,367	$ 808,568
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.50%	1.80%
Europe: | Debt securities: | Government
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 1,260	$ 46,946
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	0.10%
Europe: | Debt securities: | Health care
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 139,437	$ 197,569
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	4.20%	0.50%
Europe: | Debt securities: | Industrials
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 56,557	$ 291,950
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	1.70%	0.70%
Europe: | Debt securities: | Information technology
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 26,818	$ 71,168
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.80%	0.20%
Europe: | Debt securities: | Materials
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 198,828	$ 377,460
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	6.00%	0.80%
Europe: | Debt securities: | Telecommunication services
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 158,004	$ 200,610
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	4.80%	0.40%
Europe: | Debt securities: | Utilities
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 0	$ 18,028
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	0.00%
Europe: | Equity securities:
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 697	$ 9,122,229
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	20.20%
Europe: | Equity securities: | Consumer discretionary
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 452	$ 270,370
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	0.60%
Europe: | Equity securities: | Consumer staples
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 0	$ 145,108
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	0.30%
Europe: | Equity securities: | Energy
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 0	$ 21,791
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	0.00%
Europe: | Equity securities: | Financials
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 245	$ 6,239,424
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	13.80%
Europe: | Equity securities: | Government
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 0	$ 40,290
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	0.10%
Europe: | Equity securities: | Health care
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 0	$ 79,582
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	0.20%
Europe: | Equity securities: | Industrials
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 0	$ 1,499,142
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	3.30%
Europe: | Equity securities: | Information technology
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 0	$ 1,646
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	0.00%
Europe: | Equity securities: | Materials
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 0	$ 475,306
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	1.10%
Europe: | Equity securities: | Telecommunication services
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 0	$ 4,834
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	0.00%
Europe: | Equity securities: | Utilities
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 0	$ 344,736
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	0.80%
Asia and other: | Debt securities:
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 49,325	$ 962,870
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	1.50%	2.20%
Asia and other: | Debt securities: | Consumer discretionary
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 9,651	$ 102,531
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.30%	0.20%
Asia and other: | Debt securities: | Consumer staples
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 12,851	$ 33,061
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.40%	0.10%
Asia and other: | Debt securities: | Energy
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 11,755	$ 193,645
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.40%	0.40%
Asia and other: | Debt securities: | Financials
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 1,087	$ 27,413
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	0.10%
Asia and other: | Debt securities: | Government
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 560	$ 6,974
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	0.00%
Asia and other: | Debt securities: | Health care
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 122	$ 47,010
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	0.10%
Asia and other: | Debt securities: | Industrials
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 2,867	$ 268,710
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.10%	0.60%
Asia and other: | Debt securities: | Information technology
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 142	$ 31,983
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	0.10%
Asia and other: | Debt securities: | Materials
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 10,290	$ 248,830
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.30%	0.60%
Asia and other: | Debt securities: | Utilities
Schedule Of Investments In Marketable Securities [Line Items]
Debt securities:	$ 0	$ 2,713
Fixed income Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	0.00%
Asia and other: | Equity securities:
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 168,301	$ 3,297,242
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	5.10%	7.30%
Asia and other: | Equity securities: | Consumer discretionary
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 25,043	$ 506,761
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.80%	1.10%
Asia and other: | Equity securities: | Consumer staples
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 17,393	$ 29,863
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.50%	0.10%
Asia and other: | Equity securities: | Energy
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 11,026	$ 192,844
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.30%	0.40%
Asia and other: | Equity securities: | Financials
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 46,510	$ 986,753
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	1.40%	2.20%
Asia and other: | Equity securities: | Health care
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 1,471	$ 18,535
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.00%	0.10%
Asia and other: | Equity securities: | Industrials
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 25,865	$ 1,032,225
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.80%	2.30%
Asia and other: | Equity securities: | Information technology
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 20,858	$ 244,433
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.60%	0.50%
Asia and other: | Equity securities: | Materials
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 15,397	$ 96,326
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.50%	0.20%
Asia and other: | Equity securities: | Telecommunication services
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 2,446	$ 34,678
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.10%	0.10%
Asia and other: | Equity securities: | Utilities
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities:	$ 2,292	$ 154,824
Equity Securities: Fair Value as a Percentage of Investments of Consolidated Funds (as a percent)	0.10%	0.30%