Concentration (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Concentration Risk [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 84,079	$ 122,300	$ 133,785
Customer Concentration Risk
Concentration Risk [Line Items]
Revenue accounted by major clients	20.00%
Westwood Management | Sales Revenue, Net | Customer Concentration Risk
Concentration Risk [Line Items]
Revenue accounted by major clients	3.20%	4.00%	4.80%
Asset Management [Member] | Sales Revenue, Net | Customer Concentration Risk
Concentration Risk [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 1,863	$ 1,868	$ 6,312
Investment Performance [Member] | Sales Revenue, Net | Customer Concentration Risk
Concentration Risk [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 764	$ 2,984	$ 0