Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Unrealized Gain (Loss) on Derivatives			$ (1,708)
NET INCOME		$ 336,350
Other comprehensive income (loss):
Foreign currency translation adjustment	(113,429)	(41,547)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax			2,718
Reclassification from AOCI, Current Period, Tax			1,708
Consolidated Legg Mason, Inc.
NET INCOME	7,934	336,350	286,703
Other comprehensive income (loss):
Foreign currency translation adjustment	(71,882)	48,556	(32,924)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax			2,493
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax			(2,718)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax			2,718
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax	(4,172)	3,046	(9,860)
Total other comprehensive income (loss)	(76,054)	51,602	(40,291)
COMPREHENSIVE INCOME	(68,120)	387,952	246,412
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest	41,180	50,894	59,600
COMPREHENSIVE INCOME ATTRIBUTABLE TO LEGG MASON, INC.	$ (109,300)	$ 337,058	$ 186,812