Equity-based Compensation - Schedule of OM Asset Management Equity Incentive Plan Other Than Options (Details) - Acadian Asset Management Inc - Restricted stock units - $ / shares	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Number of shares
Outstanding at beginning of year (in shares)	62,689	48,797	71,664
Granted during the year (in shares)	43,493	44,639	49,494
Forfeited during the year (in shares)	0	0	(15,823)
Vested during the year (in shares)	(38,461)	(30,747)	(56,538)
Outstanding at end of year (in shares)	67,721	62,689	48,797
Weighted average grant date fair value per share
Outstanding at beginning of period, (in dollars per share)	$ 22.80	$ 24.19	$ 20.95
Granted during the year (in dollars per share)	26.99	21.68	24.04
Forfeited during the year (in dollars per share)	0	0	25.05
Vested during the year (in dollars per share)	23.06	23.54	19.72
Outstanding at end of period, (in dollars per share)	$ 25.34	$ 22.80	$ 24.19

Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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-Topic 718
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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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Number of shares under non-option equity instrument agreements that were cancelled as a result of occurrence of a terminating event.

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Net number of non-option equity instruments granted to participants.

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Number of equity instruments other than options outstanding, including both vested and non-vested instruments.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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