Financial Data of Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Segment Reporting Information [Line Items]
Total Management and Advisory Fees, Net	$ 578,723	$ 488,048	$ 1,060,856	$ 959,724
Performance Fees Realized - Carried Interest	183,288	55,929	477,458	69,489
Performance Fees Realized - Incentive Fees	76,104	11,631	99,845	16,910
Performance Fees Unrealized - Carried Interest	456,706	84,290	634,053	383,086
Performance Fees Unrealized - Incentive Fees	938	(16,436)	106,736	50,699
Total Performance Fees	717,036	135,414	1,318,092	520,184
Investment Income (Loss), Realized	75,490	5,758	117,843	22,093
Investment Income (Loss), Unrealized	56,570	(10,519)	162,800	62,307
Total Investment Income (Loss)	132,060	(4,761)	280,643	84,400
Interest and Dividend Revenue	13,814	9,267	26,371	16,903
Other	(1,163)	(765)	981	(1,972)
Total Revenues	1,440,470	627,203	2,686,943	1,579,239
Compensation	478,981	533,367	930,411	1,028,622
Performance Fee Compensation - Realized Carried Interest	75,910	7,898	165,347	15,836
Performance Fee Compensation - Realized Incentive Fees	35,014	5,576	45,522	9,828
Performance Fee Compensation - Unrealized Carried Interest	172,824	36,815	268,296	121,359
Performance Fee Compensation - Unrealized Incentive Fees	3,084	(9,595)	47,562	3,183
Total Compensation and Benefits	765,813	574,061	1,457,138	1,178,828
Total Expenses	914,762	739,819	1,749,863	1,523,612
Economic Income	566,674	135,614	1,045,256	591,999
Segment Assets	27,742,878		27,742,878
Operating Segments
Segment Reporting Information [Line Items]
Management and Advisory Fees, Base Management Fees	425,674	381,344	834,421	776,850
Management and Advisory Fees, Advisory Fees	120,734	93,372	187,754	169,218
Management and Advisory Fees, Transaction and Other Fees, Net	66,464	49,453	104,438	87,924
Management and Advisory Fees, Management Fee Offsets	(10,535)	(7,973)	(20,197)	(21,023)
Total Management and Advisory Fees, Net	602,337	516,196	1,106,416	1,012,969
Performance Fees Realized - Carried Interest	183,288	55,929	477,458	69,489
Performance Fees Realized - Incentive Fees	74,867	11,692	99,594	16,971
Performance Fees Unrealized - Carried Interest	456,706	84,290	634,053	383,086
Performance Fees Unrealized - Incentive Fees	4,358	(17,074)	112,113	51,047
Total Performance Fees	719,219	134,837	1,323,218	520,593
Investment Income (Loss), Realized	54,586	9,360	92,696	32,852
Investment Income (Loss), Unrealized	42,533	(25,624)	139,194	34,290
Total Investment Income (Loss)	97,119	(16,264)	231,890	67,142
Interest and Dividend Revenue	15,342	10,391	30,003	19,736
Other	(1,164)	(828)	979	(2,035)
Total Revenues	1,432,853	644,332	2,692,506	1,618,405
Compensation	306,477	268,884	573,454	523,656
Performance Fee Compensation - Realized Carried Interest	75,910	7,899	165,347	15,837
Performance Fee Compensation - Realized Incentive Fees	35,014	5,575	45,522	9,827
Performance Fee Compensation - Unrealized Carried Interest	172,824	36,815	268,296	121,358
Performance Fee Compensation - Unrealized Incentive Fees	3,084	(9,596)	47,562	3,183
Total Compensation and Benefits	593,309	309,577	1,100,181	673,861
Other Operating Expenses	120,152	113,038	234,596	222,559
Total Expenses	713,461	422,615	1,334,777	896,420
Economic Income	719,392	221,717	1,357,729	721,985
Segment Assets	14,196,338		14,196,338
Operating Segments | Private Equity
Segment Reporting Information [Line Items]
Management and Advisory Fees, Base Management Fees	86,621	87,475	172,867	173,264
Management and Advisory Fees, Transaction and Other Fees, Net	38,348	14,951	62,801	33,048
Management and Advisory Fees, Management Fee Offsets	(1,950)	(672)	(2,430)	(4,454)
Total Management and Advisory Fees, Net	123,019	101,754	233,238	201,858
Performance Fees Realized - Carried Interest	3,899	28,781	143,791	32,714
Performance Fees Unrealized - Carried Interest	182,926	(87,893)	98,972	(53,842)
Total Performance Fees	186,825	(59,112)	242,763	(21,128)
Investment Income (Loss), Realized	21,586	(6,195)	45,748	7,716
Investment Income (Loss), Unrealized	21,088	(28,337)	52,799	(11,868)
Total Investment Income (Loss)	42,674	(34,532)	98,547	(4,152)
Interest and Dividend Revenue	3,251	3,114	6,235	5,534
Other	366	562	790	347
Total Revenues	356,135	11,786	581,573	182,459
Compensation	63,747	53,775	123,950	106,322
Performance Fee Compensation - Realized Carried Interest	877	804	17,123	1,124
Performance Fee Compensation - Unrealized Carried Interest	88,111	(8,259)	104,730	(9,311)
Total Compensation and Benefits	152,735	46,320	245,803	98,135
Other Operating Expenses	32,178	30,521	61,346	59,402
Total Expenses	184,913	76,841	307,149	157,537
Economic Income	171,222	(65,055)	274,424	24,922
Segment Assets	4,118,466		4,118,466
Operating Segments | Real Estate
Segment Reporting Information [Line Items]
Management and Advisory Fees, Base Management Fees	137,000	127,817	275,346	275,619
Management and Advisory Fees, Transaction and Other Fees, Net	19,013	25,151	28,153	39,563
Management and Advisory Fees, Management Fee Offsets	(6,312)	(5,357)	(13,598)	(13,984)
Total Management and Advisory Fees, Net	149,701	147,611	289,901	301,198
Performance Fees Realized - Carried Interest	143,481	13,539	212,254	22,156
Performance Fees Realized - Incentive Fees	31,102	7,766	34,194	7,765
Performance Fees Unrealized - Carried Interest	259,972	144,510	540,048	366,010
Performance Fees Unrealized - Incentive Fees	(32,279)	(1,526)	(29,879)	6,388
Total Performance Fees	402,276	164,289	756,617	402,319
Investment Income (Loss), Realized	18,577	9,067	28,111	16,879
Investment Income (Loss), Unrealized	30,636	14,944	90,939	40,856
Total Investment Income (Loss)	49,213	24,011	119,050	57,735
Interest and Dividend Revenue	4,396	3,277	8,694	5,829
Other	(274)	(590)	(407)	(1,299)
Total Revenues	605,312	338,598	1,173,855	765,782
Compensation	73,792	76,576	143,251	145,465
Performance Fee Compensation - Realized Carried Interest	55,005	3,401	80,868	7,478
Performance Fee Compensation - Realized Incentive Fees	15,733	3,871	17,457	3,873
Performance Fee Compensation - Unrealized Carried Interest	78,604	31,677	167,661	85,952
Performance Fee Compensation - Unrealized Incentive Fees	(16,329)	(629)	(15,295)	3,139
Total Compensation and Benefits	206,805	114,896	393,942	245,907
Other Operating Expenses	27,617	26,560	56,079	55,484
Total Expenses	234,422	141,456	450,021	301,391
Economic Income	370,890	197,142	723,834	464,391
Segment Assets	5,842,665		5,842,665
Operating Segments | Hedge Fund Solutions
Segment Reporting Information [Line Items]
Management and Advisory Fees, Base Management Fees	100,113	84,278	192,904	166,099
Management and Advisory Fees, Transaction and Other Fees, Net	61	65	65	157
Management and Advisory Fees, Management Fee Offsets	(714)	(375)	(1,038)	(710)
Total Management and Advisory Fees, Net	99,460	83,968	191,931	165,546
Performance Fees Realized - Incentive Fees	13,845	1,175	27,554	4,473
Performance Fees Unrealized - Incentive Fees	20,989	(10,981)	76,490	12,206
Total Performance Fees	34,834	(9,806)	104,044	16,679
Investment Income (Loss), Realized	13,668	929	14,520	1,432
Investment Income (Loss), Unrealized	(12,054)	(3,636)	(8,141)	4,735
Total Investment Income (Loss)	1,614	(2,707)	6,379	6,167
Interest and Dividend Revenue	1,878	495	3,094	881
Other	(254)	27	(169)	(100)
Total Revenues	137,532	71,977	305,279	189,173
Compensation	36,844	34,559	70,712	62,792
Performance Fee Compensation - Realized Incentive Fees	5,116	(345)	10,138	1,033
Performance Fee Compensation - Unrealized Incentive Fees	7,666	(2,820)	27,502	4,474
Total Compensation and Benefits	49,626	31,394	108,352	68,299
Other Operating Expenses	16,535	14,506	31,694	28,440
Total Expenses	66,161	45,900	140,046	96,739
Economic Income	71,371	26,077	165,233	92,434
Segment Assets	1,298,257		1,298,257
Operating Segments | Credit
Segment Reporting Information [Line Items]
Management and Advisory Fees, Base Management Fees	101,940	81,774	193,304	161,868
Management and Advisory Fees, Transaction and Other Fees, Net	9,002	9,184	13,376	14,909
Management and Advisory Fees, Management Fee Offsets	(1,559)	(1,569)	(3,131)	(1,875)
Total Management and Advisory Fees, Net	109,383	89,389	203,549	174,902
Performance Fees Realized - Carried Interest	35,908	13,609	121,413	14,619
Performance Fees Realized - Incentive Fees	29,920	2,751	37,846	4,733
Performance Fees Unrealized - Carried Interest	13,808	27,673	(4,967)	70,918
Performance Fees Unrealized - Incentive Fees	15,648	(4,567)	65,502	32,453
Total Performance Fees	95,284	39,466	219,794	122,723
Investment Income (Loss), Realized	901	5,638	4,229	6,321
Investment Income (Loss), Unrealized	4,381	(9,156)	5,474	55
Total Investment Income (Loss)	5,282	(3,518)	9,703	6,376
Interest and Dividend Revenue	4,071	1,752	8,618	4,177
Other	(1,063)	(787)	765	(1,025)
Total Revenues	212,957	126,302	442,429	307,153
Compensation	55,941	42,845	101,462	79,988
Performance Fee Compensation - Realized Carried Interest	20,028	3,694	67,356	7,235
Performance Fee Compensation - Realized Incentive Fees	14,165	2,049	17,927	4,921
Performance Fee Compensation - Unrealized Carried Interest	6,109	13,397	(4,095)	44,717
Performance Fee Compensation - Unrealized Incentive Fees	11,747	(6,147)	35,355	(4,430)
Total Compensation and Benefits	107,990	55,838	218,005	132,431
Other Operating Expenses	22,961	15,749	43,923	32,845
Total Expenses	130,951	71,587	261,928	165,276
Economic Income	82,006	54,715	180,501	141,877
Segment Assets	2,258,620		2,258,620
Operating Segments | Financial Advisory
Segment Reporting Information [Line Items]
Management and Advisory Fees, Advisory Fees	120,734	93,372	187,754	169,218
Management and Advisory Fees, Transaction and Other Fees, Net	40	102	43	247
Total Management and Advisory Fees, Net	120,774	93,474	187,797	169,465
Investment Income (Loss), Realized	(146)	(79)	88	504
Investment Income (Loss), Unrealized	(1,518)	561	(1,877)	512
Total Investment Income (Loss)	(1,664)	482	(1,789)	1,016
Interest and Dividend Revenue	1,746	1,753	3,362	3,315
Other	61	(40)		42
Total Revenues	120,917	95,669	189,370	173,838
Compensation	76,153	61,129	134,079	129,089
Total Compensation and Benefits	76,153	61,129	134,079	129,089
Other Operating Expenses	20,861	25,702	41,554	46,388
Total Expenses	97,014	86,831	175,633	175,477
Economic Income	23,903	8,838	13,737	(1,639)
Segment Assets	$ 678,330		$ 678,330