Equity-based Compensation - OM Asset Management Equity Incentive Plan Other Than Options (Details) - Brightsphere Equity Incentive Plan - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Restricted shares (RSA)
Number of shares
Outstanding at beginning of year (in shares)	2,500	14,010	77,217
Granted during the year (in shares)	0	0	0
Forfeited during the year (in shares)	(125)	(1,500)	(6,447)
Vested during the year (in shares)	(2,375)	(10,010)	(56,760)
Outstanding at end of year (in shares)	0	2,500	14,010
Weighted average grant date fair value per share
Outstanding at beginning of period, (in dollars per share)	$ 10.09	$ 13.26	$ 14.43
Granted during the year (in dollars per share)	0	0	0
Forfeited during the year (in dollars per share)	10.09	10.09	14.19
Vested during the year (in dollars per share)	10.09	14.53	14.75
Outstanding at end of period, (in dollars per share)	$ 0	$ 10.09	$ 13.26
Restricted stock units
Number of shares
Outstanding at beginning of year (in shares)	38,703	60,364	62,899
Granted during the year (in shares)	59,999	15,548	105,678
Forfeited during the year (in shares)	(3,003)	(2,345)	(30,927)
Vested during the year (in shares)	(24,035)	(34,864)	(77,286)
Outstanding at end of year (in shares)	71,664	38,703	60,364
Weighted average grant date fair value per share
Outstanding at beginning of period, (in dollars per share)	$ 15.33	$ 10.53	$ 11.79
Granted during the year (in dollars per share)	22.62	22.06	10.20
Forfeited during the year (in dollars per share)	17.55	10.30	10.83
Vested during the year (in dollars per share)	16.51	10.35	10.99
Outstanding at end of period, (in dollars per share)	$ 20.95	$ 15.33	$ 10.53
Performance-based RSAs
Number of shares
Outstanding at beginning of year (in shares)	0	83,092	258,678
Granted during the year (in shares)	0	0	0
Vested during the year (in shares)	0	(36,007)	0
Other movements (in shares)	0	(47,085)	(175,586)
Outstanding at end of year (in shares)	0	0	83,092
Weighted average grant date fair value per share
Outstanding at beginning of period, (in dollars per share)	$ 0	$ 9.78	$ 10.11
Vested during the year (in dollars per share)	0	9.78	0
Other movements (in dollars per share)	0	9.78	10.26
Outstanding at end of period, (in dollars per share)	$ 0	$ 0	$ 9.78
Performance-based RSUs
Number of shares
Outstanding at beginning of year (in shares)	9,013	9,013	9,013
Granted during the year (in shares)	0	0
Vested during the year (in shares)	(7,932)	0	0
Other movements (in shares)	(1,081)	0	0
Outstanding at end of year (in shares)	0	9,013	9,013
Weighted average grant date fair value per share
Outstanding at beginning of period, (in dollars per share)	$ 14.62	$ 14.62	$ 14.62
Vested during the year (in dollars per share)	14.62	0	0
Other movements (in dollars per share)	14.62	0	0
Outstanding at end of period, (in dollars per share)	$ 0	$ 14.62	$ 14.62