Unconsolidated VIE's (Details 9) - Variable Interest Entity, Not Primary Beneficiary [Member] - USD ($) $ in Thousands		Sep. 30, 2016	Mar. 31, 2016
Variable Interest Entity
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	[1]	$ 36,648	$ 32,091
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	[2]	54,322	42,735
Assets Under Management		27,709,902	17,170,697
CDO and CLO [Member]
Variable Interest Entity
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	[1]	0	0
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	[2]	0	288
Real Estate Investment Trusts [Member]
Variable Interest Entity
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	[1]	11,328	9,540
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	[2]	13,131	14,595
Other sponsored investments fund [Member]
Variable Interest Entity
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	[1]	25,320	22,551
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	[2]	$ 41,191	$ 27,852

[1] Amounts are related to investments in proprietary funds products.

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