Equity-based Compensation - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)	4,500,000
Compensation expense	$ (47,700,000)	$ (23,200,000)	$ 100,000
Compensation costs to be recognized next year	8,800,000
Total intrinsic value of options exercised		24,700,000	5,100,000
Amount received related to the exercise of options		100,000	0.0
Tax benefit related to exercise of options		$ 100,000	$ 300,000
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized share based compensation expense	$ 7,300,000
Unrecognized share based compensation expense recognition period	1 year 10 months 24 days
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option awards outstanding (in shares)	0	0	1,659,000	2,470,463
Shares granted (in shares)	0	0	0
Options vested (in shares)	0
Exercised during the year (in shares)	0	1,659,000	736,463
Fair value options vested		$ 0.0	$ 1,300,000
Total intrinsic value of options exercised		0	14,128,440
Brightsphere Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 3,000,000.0	900,000	1,200,000
Income tax benefit	$ 100,000	$ 100,000	$ 200,000
Brightsphere Equity Incentive Plan | Restricted stock units | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year
Brightsphere Equity Incentive Plan | Restricted stock units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years