Business Segment Information and Geographic Data - Schedule of Operating Income (Loss) by Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Total segment operating loss	$ (3,400)	$ (8,300)
Interest expense	(300)	(100)
Net income (loss) from AAM fund activities		(900)
Other income (expense), net	15,100	(500)
Loss from continuing operations before income taxes	11,400	(8,800)
Intangible Impairment [Member]
Total segment operating loss		(6,200)
Operating Segments [Member]
Total segment operating loss	(100)	(3,600)
Operating Segments [Member] | Asset Management Business [Member]
Total segment operating loss	100	(3,600)
Operating Segments [Member] | Sports Investment Platform [Member]
Total segment operating loss	(200)	(3,600)
Corporate and Unallocated [Member]
Total segment operating loss	(3,200)	(3,300)
Restructuring and Other [Member]
Total segment operating loss	$ (100)	$ 4,800