Variable Interest Entities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Variable Interest Entities
Assets Under Management	$ 24,229,000
Corporate Investment	51,324	$ 56,485
Westwood Funds
Variable Interest Entities
Assets Under Management	4,242,000
Corporate Investment	6,000
Amount at Risk	6,000
Common Trust Funds
Variable Interest Entities
Assets Under Management	2,564,000
Corporate Investment	2,000
Amount at Risk	2,000
Limited Liability Company [Member]
Variable Interest Entities
Assets Under Management	116,000
Corporate Investment	0
Amount at Risk	0
UCITS Fund
Variable Interest Entities
Assets Under Management	412,000
Corporate Investment	2,000
Amount at Risk	2,000
Private Wealth
Variable Interest Entities
Assets Under Management	2,886,000
Institutional
Variable Interest Entities
Assets Under Management	$ 14,009,000