Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
OTHER NON-OPERATING INCOME (EXPENSE)
Net Income (Loss) Attributable to Noncontrolling Interest	$ 11,888	$ 391
Consolidated Legg Mason, Inc.
OPERATING REVENUES
Distribution and service fees	91,382	96,860
Other	1,008	688
Revenues	700,165	708,650
OPERATING EXPENSES
Compensation and benefits	358,625	315,052
Distribution and servicing	124,663	149,288
Communications and technology	52,732	48,677
Occupancy	33,142	25,987
Amortization of intangible assets	5,703	657
Other	51,745	44,446
Total Operating Expenses	626,610	584,107
OPERATING INCOME	73,555	124,543
OTHER NON-OPERATING INCOME (EXPENSE)
Interest income	1,848	1,317
Interest expense	(24,565)	(11,949)
Other income (expense), net	6,585	5,711
Total Other Non-Operating Income (Expense)	(12,904)	(4,514)
INCOME BEFORE INCOME TAX PROVISION	60,651	120,029
Income tax provision	15,311	25,090
NET INCOME	45,340	94,939
Net Income (Loss) Attributable to Noncontrolling Interest	11,888	391
NET INCOME ATTRIBUTABLE TO LEGG MASON, INC.	$ 33,452	$ 94,548
NET INCOME PER SHARE ATTRIBUTABLE TO LEGG MASON, INC. COMMON SHAREHOLDERS
Basic (in dollars per share)	$ 0.31	$ 0.85
Diluted (in dollars per share)	0.31	0.84
Common Stock, Dividends, Per Share, Declared	$ 0.22	$ 0.20
Consolidated Entity Excluding Consolidated Investment Vehicles Before Eliminations [Member]
OTHER NON-OPERATING INCOME (EXPENSE)
NET INCOME ATTRIBUTABLE TO LEGG MASON, INC.	$ 33,452	$ 94,548
Consolidated Investment Vehicles [Member]
OTHER NON-OPERATING INCOME (EXPENSE)
Other income (expense), net	3,228	407
Separate Accounts [Member] | Consolidated Legg Mason, Inc.
OPERATING REVENUES
Investment Advisory Fees	226,853	208,104
Mutual Funds [Member] | Consolidated Legg Mason, Inc.
OPERATING REVENUES
Investment Advisory Fees	363,463	384,345
Performance Fees [Member] | Consolidated Legg Mason, Inc.
OPERATING REVENUES
Investment Advisory Fees	$ 17,459	$ 18,653