Variable Interest Entities and Consolidation of Investment Vehicles Information about Investments in CIV's (Details) $ in Thousands	3 Months Ended
	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Jun. 30, 2016
Variable Interest Entity
Employee Owned Funds	1	1	1
Variable Interest Entity, Primary Beneficiary, Number of Collateralized Securites Vehicles	3	3	9
Number of Sponsored Investment Fund Vie	2	3	3
Derivative, Notional Amount	$ 20,253
Consolidated Investment Vehicles [Member] | Proprietary Funds [Member]
Variable Interest Entity
Assets, Fair Value Disclosure	36,026	$ 28,300
Interest Rate Swap [Member]
Variable Interest Entity
Derivative, Notional Amount	$ 20,253