Components Intangible Assets (Details 1) - USD ($) $ in Thousands	Jun. 30, 2016		Mar. 31, 2016	Dec. 31, 2015
Finite-Lived and Indefinite-lived Intangible Assets
Cost	$ 395,011		$ 259,513
Accumulated amortization	(176,988)		(171,169)
Total	218,023	[1]	88,344
Indefinite-life intangible assets	4,031,433		3,058,141
U.S. Domestic Mutual Fund Management Contracts
Finite-Lived and Indefinite-lived Intangible Assets
Indefinite-life intangible assets	2,106,351		2,106,351
Reporting Unit, Percentage of Fair Value in Excess of Carrying Amount				48.00%
Other Fund Management Contracts [Member]
Finite-Lived and Indefinite-lived Intangible Assets
Indefinite-life intangible assets	545,938		560,499
Trade Names
Finite-Lived and Indefinite-lived Intangible Assets
Indefinite-life intangible assets	87,040	[1]	57,187
Permal [Member] | Other Fund Management Contracts [Member]
Finite-Lived and Indefinite-lived Intangible Assets
Indefinite-life intangible assets	334,104		334,104
EnTrust Capital [Member] | Other Fund Management Contracts [Member]
Finite-Lived and Indefinite-lived Intangible Assets
Indefinite-life intangible assets	452,800		0
Clarion Partners [Member] | Other Fund Management Contracts [Member]
Finite-Lived and Indefinite-lived Intangible Assets
Indefinite-life intangible assets	505,200		0
Consolidated Legg Mason, Inc.
Finite-Lived and Indefinite-lived Intangible Assets
Intangible assets, net	4,249,456		$ 3,146,485
EnTrust Capital [Member]
Finite-Lived and Indefinite-lived Intangible Assets
Total	34,317
EnTrust Capital [Member] | Trade Names
Finite-Lived and Indefinite-lived Intangible Assets
Indefinite-life intangible assets	7,400
Clarion Partners [Member]
Finite-Lived and Indefinite-lived Intangible Assets
Total	100,268
Clarion Partners [Member] | Trade Names
Finite-Lived and Indefinite-lived Intangible Assets
Indefinite-life intangible assets	$ 23,100

[1] As of June 30, 2016, Amortizable intangible asset management contracts, net and Trade names include $100,268 and $23,100, respectively, related to the acquisition of Clarion Partners and $34,317 and $7,400, respectively, related to the acquisition of EnTrust. As discussed above, the Clarion Partners and EnTrust purchase accounting is preliminary and subject to adjustment during the one-year measurement period following the respective closing date for each acquisition, as permitted by the related accounting guidance. Such adjustments could be material. See Note 3 for additional information.