Variable Interest Entities and Consolidation of Investment Vehicles (Details 9) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013		Mar. 31, 2013
CLOs
Variable Interest Entity [Line Items]
Equity Interests on the Consolidated Balance Sheet	$ 0	[1]	$ 0	[1]
Maximum Risk of Loss	675	[2]	496	[2]
Real Estate Investment Trusts
Variable Interest Entity [Line Items]
Equity Interests on the Consolidated Balance Sheet	1,009	[1]	989	[1]
Maximum Risk of Loss	3,819	[2]	2,644	[2]
Other sponsored investment funds
Variable Interest Entity [Line Items]
Equity Interests on the Consolidated Balance Sheet	34,823	[1]	43,104	[1]
Maximum Risk of Loss	83,455	[2]	87,121	[2]
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Equity Interests on the Consolidated Balance Sheet	35,832	[1]	44,093	[1]
Maximum Risk of Loss	87,949	[2]	90,261	[2]
Amount of VIE Equity interests on consolidated balance sheet related to investments in proprietary funds products	25,935		33,918
AUM of unconsolidated VIEs	$ 18,219,648		$ 17,090,267

[1] Includes $25,935 and $33,918 related to investments in proprietary funds products as of September 30, 2013, and March 31, 2013, respectively.

[2] Includes equity investments the Company has made or is required to make and any earned but uncollected management fees.