Earnings (Loss) Per Share - Computation of Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Net Income (Loss)	$ 72,511	$ 40,934	$ 200,822	$ 58,149
Noncontrolling interests	(13,775)	(11,286)	(42,531)	(21,507)
Net Income (Loss) Attributable to Virtus Investment Partners, Inc.	$ 58,736	$ 29,648	$ 158,291	$ 36,642
Shares:
Basic: Weighted-average number of common shares outstanding (in shares)	7,691	7,684	7,688	7,611
Plus: Incremental shares from assumed conversion of dilutive instruments (in shares)	293	313	340	347
Diluted: Weighted-average number of common shares outstanding (in shares)	7,984	7,997	8,028	7,958
Earnings (Loss) Per share—Basic (in $ per share)	$ 7.64	$ 3.86	$ 20.59	$ 4.81
Earnings (Loss) Per Share—Diluted (in $ per share)	$ 7.36	$ 3.71	$ 19.72	$ 4.60