Investments - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended						3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended			3 Months Ended	6 Months Ended				6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012	Jun. 30, 2013 EMCP III [Member]	Jun. 30, 2013 Trilantic [Member]	Dec. 31, 2012 Trilantic [Member]	Jun. 30, 2013 G5 [Member]	Jun. 30, 2012 G5 [Member]	Jun. 30, 2013 G5 [Member]	Jun. 30, 2012 G5 [Member]	Dec. 31, 2012 G5 [Member]	Jun. 30, 2013 ABS [Member]	Jun. 30, 2012 ABS [Member]	Jun. 30, 2013 ABS [Member]	Jun. 30, 2012 ABS [Member]	Dec. 31, 2012 ABS [Member]	Jun. 30, 2012 Pan [Member]	Jun. 30, 2013 Pan [Member]	Jun. 30, 2012 Pan [Member]	Dec. 31, 2012 Pan [Member]	Dec. 31, 2008 Pan [Member]	Jun. 30, 2013 Pan [Member] Variable Interest Entity, Primary Beneficiary [Member]	Jun. 30, 2013 EMP III [Member] Variable Interest Entity, Primary Beneficiary [Member]	Jun. 30, 2013 EMP III [Member] EMCP III [Member]	Jun. 30, 2013 Parent [Member] EMCP III [Member]	Jun. 30, 2013 Noncontrolling Interest [Member] EMCP III [Member]
Schedule of Investments [Line Items]
Assets	$ 1,032,963	$ 973,858	$ 1,032,963	$ 973,858	$ 1,145,218																			$ 702	$ 3,663
Liabilities	512,305		512,305		604,742																			518	259
Subscribed capital commitments						201,000
Capital commitment																										10,750	1,000	9,750
Unfunded commitments for capital contributions	10,830		10,830				5,000																			7,375	686
Net realized and unrealized gains (losses) on private equity fund investments, including performance fees	2,073	(301)	2,550	(608)
Previously received carried interest subject to repayment	2,701		2,701
Investments Disclosure							14,999	14,999
Equity method investment (as a percent)									49.00%		49.00%			45.00%		45.00%				68.00%		50.00%
Income from Equity Method Investments	1,015	719	1,771	3,104					247	(93)	184	1,270		768	912	1,642	1,622		(100)	(55)	212
Equity method investment	62,818		62,818		69,320				18,886		18,886		19,720	43,932		43,932		46,851		0		2,749	4,158
Goodwill																								3,020
Intangible assets	32,764		32,764		35,397																			1,440
Intangible assets, useful life																								7 years
Amortization of intangible assets	$ 647	$ 649	$ 1,294	$ 1,396