Investments - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended								12 Months Ended
	Jun. 30, 2014	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2010	Feb. 28, 2010	Dec. 31, 2008
Schedule of Investments [Line Items]
Marketable Securities		$ 43,787,000				$ 37,985,000				$ 43,787,000	$ 37,985,000
Unfunded commitments for capital contributions		8,162,000								8,162,000
Participation in Successor Funds		12,000,000								12,000,000
Net realized and unrealized gains (losses) on private equity fund investments, including performance fees										5,086,000	7,858,000	$ 8,060,000
Previously received carried interest subject to repayment		0								0
Limited partnership investment		0				4,014,000				0	4,014,000
Cost Method Investments				$ 1,079,000
Income (loss) from equity method investments		2,016,000	$ 929,000	$ 1,998,000	$ 1,107,000	1,799,000	$ 1,102,000	$ 2,038,000	$ 241,000	6,050,000	5,180,000	8,326,000
Equity Method Investment		86,287,000				76,581,000				86,287,000	76,581,000
Amortization of intangible assets										2,484,000	2,586,000	2,586,000
Variable Interest Entity, Primary Beneficiary [Member]
Schedule of Investments [Line Items]
Consolidated assets		31,100,000				10,487,000				31,100,000	10,487,000
Consolidated liabilities		$ 10,914,000				7,487,000				$ 10,914,000	7,487,000
Atalanta Sosnoff [Member]
Schedule of Investments [Line Items]
Limited partnership investment						4,014,000					4,014,000
Equity method investment (as a percent)		49.00%								49.00%
Equity Method Investment		$ 23,990,000				0				$ 23,990,000	0
EMCP II [Member]
Schedule of Investments [Line Items]
Distribution Made to Limited Partner, Cash Distributions Paid										3,194,000
Trilantic IV [Member]
Schedule of Investments [Line Items]
Distribution Made to Limited Partner, Cash Distributions Paid										2,907,000
EMP III [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Schedule of Investments [Line Items]
Consolidated assets		6,030,000				7,327,000				6,030,000	7,327,000
Consolidated liabilities		$ 164,000				75,000				$ 164,000	$ 75,000
Trilantic [Member]
Schedule of Investments [Line Items]
Issued LP Units (in shares)														500,000	500,000
Limited partnership investment														$ 16,090,000
G5 Evercore [Member]
Schedule of Investments [Line Items]
Equity method investment (as a percent)		49.00%								49.00%
Equity interest issued or issuable (in shares)	131,000										131,000
Equity interest issued or issuable, value	$ 7,232,000							$ 7,232,000
Contingent consideration	$ 7,916,000
Income (loss) from equity method investments										$ 662,000	$ (48,000)	2,126,000
Equity Method Investment		$ 20,730,000				32,756,000				$ 20,730,000	32,756,000
ABS [Member]
Schedule of Investments [Line Items]
Equity method investment (as a percent)		45.00%								45.00%
Income (loss) from equity method investments										$ 5,388,000	5,228,000	6,255,000
Equity Method Investment		$ 41,567,000				43,825,000				41,567,000	43,825,000
ECP II [Member]
Schedule of Investments [Line Items]
Distribution Made to Limited Partner, Cash Distributions Paid										3,000,000
CSI Capital [Member]
Schedule of Investments [Line Items]
Distribution Made to Limited Partner, Cash Distributions Paid										$ 2,909,000
Pan [Member]
Schedule of Investments [Line Items]
Income (loss) from equity method investments												(55,000)
Equity Method Investment																$ 4,158,000
Minimum [Member] | ECP II [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Schedule of Investments [Line Items]
Percent ownership of carried interest										8.00%
Maximum [Member] | ECP II [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Schedule of Investments [Line Items]
Percent ownership of carried interest										9.00%
EMCP III [Member]
Schedule of Investments [Line Items]
Subscribed capital commitments												201,000,000
EMCP III [Member] | EMP III [Member]
Schedule of Investments [Line Items]
Capital commitment												10,750,000
Unfunded commitments for capital contributions		4,665,000								$ 4,665,000
EMCP III [Member] | Parent [Member]
Schedule of Investments [Line Items]
Capital commitment												1,000,000
Unfunded commitments for capital contributions		391,000								391,000
EMCP III [Member] | Noncontrolling Interest [Member]
Schedule of Investments [Line Items]
Capital commitment												9,750,000
Trilantic [Member]
Schedule of Investments [Line Items]
Investment		12,812,000				13,455,000				12,812,000	13,455,000
Trilantic [Member] | Trilantic IV [Member]
Schedule of Investments [Line Items]
Investment		8,000								8,000		29,000	$ 1,091,000
Trilantic [Member] | Trilantic V [Member]
Schedule of Investments [Line Items]
Capital commitment		5,000,000								5,000,000
Unfunded commitments for capital contributions		3,246,000								3,246,000
Investment		636,000				689,000				636,000	689,000	$ 825,000
Private Equity Funds [Member]
Schedule of Investments [Line Items]
Equity Method Investment		26,473,000				36,551,000				26,473,000	36,551,000
Private Equity Funds [Member] | ECP II [Member]
Schedule of Investments [Line Items]
Cash		748,000								748,000
Escrow Deposit		87,000								87,000
Seller Note		66,000								66,000
Marketable Securities		82,000								82,000
Equity Method Investment		983,000				4,043,000				983,000	4,043,000
Private Equity Funds [Member] | EMCP III [Member]
Schedule of Investments [Line Items]
Equity Method Investment		5,786,000				7,272,000				5,786,000	7,272,000
Private Equity Funds [Member] | Trilantic V [Member]
Schedule of Investments [Line Items]
Equity Method Investment		$ 4,117,000				$ 2,911,000				$ 4,117,000	$ 2,911,000