Subsequent Events - Additional Information (Details) - USD ($)						3 Months Ended			9 Months Ended
	Nov. 04, 2021	Nov. 01, 2021	Oct. 12, 2021	Sep. 13, 2021	Jul. 01, 2019	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Subsequent Event [Line Items]
Dividends declared per share of common stock						$ 0.15		$ 0.06	$ 0.36	$ 0.16
Subsequent Event
Subsequent Event [Line Items]
Dividends declared per share of common stock	$ 0.17
Dividends, date of declared	Nov. 04, 2021
Dividends payable date	Dec. 10, 2021
Dividends payable, date of record	Dec. 27, 2021
USAA AMCO
Subsequent Event [Line Items]
Business combination, earnout payments							$ 37,500,000		$ 37,500,000
Period of time over which contingent payments will be made					4 years
USAA AMCO | Subsequent Event
Subsequent Event [Line Items]
Business combination, earnout payments			$ 37,500,000
NEC Acquisition
Subsequent Event [Line Items]
Payments to acquire business				$ 65,000,000
Business acquisition, acquired percentage				100.00%
NEC Acquisition | Subsequent Event
Subsequent Event [Line Items]
Payments to acquire business		$ 65,000,000
Outstanding borrowing		$ 7,500,000
WestEnd Purchase Agreement | Subsequent Event
Subsequent Event [Line Items]
Payments to acquire business	$ 480,000,000
Business acquisition, acquired percentage	100.00%
Period of time over which contingent payments will be made	4 years
Period of time over which contingent "catch-up" provisions payments will be made	5 years 6 months
Maximum aggregate earn-out payments	$ 320,000,000.0
Maximum annual earn-out payments	80,000,000.0
Aggregate principal amount	$ 505,000,000.0