Other Compensation Liabilities - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Profit interests compensation expense (income)	$ 19.0	$ 0.0	$ (28.0)
Redemption of profit sharing interests for cash	$ 0.3	$ 0.0	$ 2.7

The amount of profit interests compensation expense (income).

No definition available.

Name:	aami_DeferredCompensationLiabilityProfitInterestsExpenseIncome
Namespace Prefix:	aami_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration