Earnings Per Share (Tables)

6 Months Ended

Sep. 30, 2017

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	Three Months Ended September 30,				Six Months Ended September 30,
	2017		2016		2017		2016
Basic weighted-average shares outstanding for EPS	93,087		101,817		93,973		103,075
Potential common shares:
Dilutive employee stock options	409		240		417		226
Diluted weighted-average shares outstanding for EPS	93,496		102,057		94,390		103,301
Net Income Attributable to Legg Mason, Inc.	$	75,664	$	66,441	$	126,584	$	99,893
Less: Earnings (distributed and undistributed) allocated to participating securities	2,687		2,183		4,387		3,173
Net Income (Distributed and Undistributed) Allocated to Shareholders (Excluding Participating Securities)	$	72,977	$	64,258	$	122,197	$	96,720
Net Income per share Attributable to Legg Mason, Inc. Shareholders
Basic	$	0.78	$	0.63	$	1.30	$	0.94
Diluted	0.78		0.63		1.29		0.94