Variable Interest Entities (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Variable Interest Entities
Assets Under Management	$ 21,722,000,000
Trading	64,039,000	79,620,000
Westwood Funds
Variable Interest Entities
Assets Under Management	4,239,000,000
Trading	1,000,000
Risk of Loss	1,000,000
Common Trust Funds
Variable Interest Entities
Assets Under Management	2,108,000,000
Trading	3,000,000
Risk of Loss	3,000,000
Collective Investment Trusts
Variable Interest Entities
Assets Under Management	309,000,000
UCITS Fund
Variable Interest Entities
Assets Under Management	820,000,000
Trading	2,000,000
Risk of Loss	2,000,000
VIE totals
Variable Interest Entities
Assets Under Management	7,618,000,000
Trading	5,800,000	4,600,000
Private Wealth
Variable Interest Entities
Assets Under Management	1,775,000,000
Institutional
Variable Interest Entities
Assets Under Management	12,329,000,000
LLCs
Variable Interest Entities
Assets Under Management	$ 142,000,000