Earnings Per Share (Tables)

9 Months Ended

Dec. 31, 2017

Earnings Per Share [Abstract]

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

	Three Months Ended December 31,				Nine Months Ended December 31,
	2017		2016		2017		2016
Basic weighted-average shares outstanding for EPS	90,377		99,403		92,770		101,897
Potential common shares:
Dilutive employee stock options	456		165		429		205
Diluted weighted-average shares outstanding for EPS	90,833		99,568		93,199		102,102
Net Income Attributable to Legg Mason, Inc.	$	149,222	$	51,439	$	275,806	$	151,332
Less: Earnings (distributed and undistributed) allocated to participating securities	5,347		$	1,706	9,639		4,874
Net Income (Distributed and Undistributed) Allocated to Shareholders (Excluding Participating Securities)	$	143,875	$	49,733	$	266,167	$	146,458
Net Income per share Attributable to Legg Mason, Inc. Shareholders
Basic	$	1.59	$	0.50	$	2.87	$	1.44
Diluted	1.58		$	0.50	2.86		1.43