Significant Accounting Policies (Details 5) (Consolidated Legg Mason [Domain], USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2011
Consolidated Legg Mason [Domain]
Redeemable Noncontrolling Interest [Line Items]
Net income (loss) attributable to redeemable noncontrolling interests	$ 350	$ (148)	$ 168	$ 8,119
Net income (loss) reclassified to Appropriated retained earnings for consolidated investment vehicle	(5,030)	7,157	(8,076)	1,355
Total	$ (4,680)	$ 7,009	$ (7,908)	$ 9,474