Earnings Per Share (Tables)

3 Months Ended

9 Months Ended

Dec. 31, 2012

Dec. 31, 2012

Earnings Per Share, Basic and Diluted [Abstract]

Computations of basic and diluted EPS

	Three Months Ended December 31,
	2012						2011
	Basic			Diluted(1)			Basic		Diluted
Weighted-average basic shares outstanding	131,534			131,534			140,053		140,053
Potential common shares:
Employee stock options	—			—			—		29
Weighted-average diluted shares	131,534			131,534			140,053		140,082
Net Income (Loss)	$	(458,550	)	$	(458,550	)	$	35,141	$	35,141
Less: Net income (loss) attributable to noncontrolling interests	(4,680		)	(4,680		)	7,009		7,009
Net Income (Loss) Attributable to Legg Mason, Inc.	$	(453,870	)	$	(453,870	)	$	28,132	$	28,132
Net Income (Loss) per Share Attributable to Legg Mason, Inc. Common Shareholders	$	(3.45	)	$	(3.45	)	$	0.20	$	0.20

	Nine Months Ended December 31,
	2012						2011
	Basic			Diluted(1)			Basic		Diluted
Weighted-average basic shares outstanding	134,770			134,770			144,363		144,363
Potential common shares:
Employee stock options	—			—			—		65
Weighted-average diluted shares	134,770			134,770			144,363		144,428
Net Income (Loss)	$	(390,439	)	$	(390,439	)	$	154,222	$	154,222
Less: Net income (loss) attributable to noncontrolling interests	(7,908		)	(7,908		)	9,474		9,474
Net Income (Loss) Attributable to Legg Mason, Inc.	$	(382,531	)	$	(382,531	)	$	144,748	$	144,748
Net Income (Loss) per Share Attributable to Legg Mason, Inc. Common Shareholders	$	(2.84	)	$	(2.84	)	$	1.00	$	1.00

(1) Diluted shares are the same as basic shares for periods with a net loss.