Unconsolidated VIE's (Details 9) - Variable Interest Entity, Not Primary Beneficiary [Member] - USD ($) $ in Thousands		Mar. 31, 2017	Mar. 31, 2016
Variable Interest Entity
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	[1]	$ 58,723	$ 32,091
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	[2]	89,473	42,735
Assets Under Management		26,735,285	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]	11,660	9,540
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	[2]	15,763	14,595
Other sponsored investments fund [Member]
Variable Interest Entity
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	[1]	47,063	22,551
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	[2]	$ 73,710	$ 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.