Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Consolidated Legg Mason, Inc.	Consolidated Legg Mason, Inc. COMMON STOCK	Consolidated Legg Mason, Inc. ADDITIONAL PAID-IN CAPITAL	Consolidated Legg Mason, Inc. EMPLOYEE STOCK TRUST	Consolidated Legg Mason, Inc. DEFERRED COMPENSATION EMPLOYEE STOCK TRUST	Consolidated Legg Mason, Inc. RETAINED EARNINGS	Consolidated Legg Mason, Inc. ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS), NET	Clarion Partners [Member]	Clarion Partners [Member] Consolidated Legg Mason, Inc. ADDITIONAL PAID-IN CAPITAL	EnTrust Capital [Member] Consolidated Legg Mason, Inc. RETAINED EARNINGS	Management Equity Plan [Member] Consolidated Legg Mason, Inc. RETAINED EARNINGS
Stockholders' Equity Attributable to Parent			$ 11,147	$ 2,844,441	$ (29,570)	$ 29,570	$ 1,690,055	$ (60,742)
Stock options exercised			16	5,014
Deferred compensation employee stock trust			0	111
Stock-based compensation			15	18,555						$ 0
Adjustments to Additional Paid in Capital, Other				9,134
Employee tax withholdings by settlement of net share transactions			(39)	(20,963)
Shares repurchased and retired			(126)	(67,874)
APIC reclassified for MEP vesting	$ (480)			0
Shares Issued to plans					(111)	111
Distributions and forfeitures					0	0
Net Income Attributable to Legg Mason, Inc.		$ 94,548					94,548
Dividends declared							(22,338)
Reclassification from Retained Earnings to Noncontrolling Interests											$ 0	$ (480)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax		1,068						1,068
Foreign currency translation adjustment		20,664
Ending Balance at Jun. 30, 2015		4,522,206
Stockholders' Equity Attributable to Parent		4,522,206	11,013	2,788,418	(29,681)	29,681	1,761,785	(39,010)
Stockholders' Equity Attributable to Noncontrolling Interest		0
Stockholders' Equity Attributable to Parent		4,213,563	10,701	2,693,113	(26,263)	26,263	1,576,242	(66,493)
Stockholders' Equity Attributable to Noncontrolling Interest		22,202
Beginning Balance at Mar. 31, 2016		4,235,765
Stock options exercised			7	1,803
Deferred compensation employee stock trust			1	122
Stock-based compensation			34	25,860					$ 11,121	$ 11,121
Adjustments to Additional Paid in Capital, Other				0
Employee tax withholdings by settlement of net share transactions			(36)	(11,625)
Shares repurchased and retired	$ (111,673)		(347)	(111,326)
APIC reclassified for MEP vesting				(3,632)
Shares Issued to plans					(123)	123
Distributions and forfeitures					760	(760)
Net Income Attributable to Legg Mason, Inc.		33,452					33,452
Dividends declared							(23,581)
Reclassification from Retained Earnings to Noncontrolling Interests											$ (15,500)	$ (619)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax		(5,105)						(5,105)
Foreign currency translation adjustment		(17,190)
Ending Balance at Jun. 30, 2016		4,117,570
Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss)								(2,683)
Stockholders' Equity Attributable to Parent		4,094,319	$ 10,360	$ 2,605,436	$ (25,626)	$ 25,626	$ 1,569,994	$ (91,471)
Stockholders' Equity Attributable to Noncontrolling Interest		$ 23,251