Unconsolidated VIE's (Details 9) - Variable Interest Entity, Not Primary Beneficiary [Member] - USD ($) $ in Thousands		Dec. 31, 2016	Mar. 31, 2016
Variable Interest Entity
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	[1]	$ 35,804	$ 32,091
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	[2]	52,442	42,735
Assets Under Management		24,783,450	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]	11,446	9,540
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	[2]	13,167	14,595
Other sponsored investments fund [Member]
Variable Interest Entity
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	[1]	24,358	22,551
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	[2]	$ 39,275	$ 27,852

[1] Amounts are related to investments in proprietary and other fund products.

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