Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Other comprehensive income (loss):
Foreign currency translation adjustment	$ (51,147)	$ 37,835
Unrealized gains (losses) on investment securities:
Unrealized holding losses, net of tax benefit of $3, $123 and $1, respectively	0	114
Tax benefit on unrealized holding losses on securities	0	76
Unrealized gains on reverse treasury rate lock, net of tax provision of $233	405
Tax provision for unrealized gain on reverse treasury rate lock	233
Less: Net income attributable to noncontrolling interests		(2,948)	(6,421)
Consolidated Legg Mason, Inc.
NET INCOME	242,709	281,836	(359,748)
Other comprehensive income (loss):
Foreign currency translation adjustment	(88,982)	(9,424)	(23,945)
Unrealized gains (losses) on investment securities:
Unrealized holding losses, net of tax benefit of $3, $123 and $1, respectively	(5)	(184)	(1)
Tax benefit on unrealized holding losses on securities	(3)	(123)	(1)
Reclassification adjustment for losses included in net income	5	18	13
Net unrealized losses on investment securities	0	(166)	12
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax	(9,595)
Unrealized gains on reverse treasury rate lock, net of tax provision of $233	405	0	0
Reclassification for realized gain on termination of reverse treasury rate lock, net of tax provision of $233	(405)	0	0
Tax provision for unrealized gain on reverse treasury rate lock	233	0	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax	(233)	0	0
Reclassification for assets held for sale	(114)	0	0
Total other comprehensive income (loss)	(98,691)	(9,590)	(23,933)
COMPREHENSIVE INCOME	144,018	272,246	(383,681)
Less: Net income attributable to noncontrolling interests	5,629	(2,948)	(6,421)
Net Income (Loss) Attributable to Redeemable Noncontrolling Interest	5,629	1,881	971
Consolidated Entity Excluding Consolidated Investment Vehicles Before Eliminations [Member]
Unrealized gains (losses) on investment securities:
COMPREHENSIVE INCOME ATTRIBUTABLE TO LEGG MASON, INC.	$ 138,389	$ 275,194	$ (377,260)