Cover - shares	3 Months Ended
	Mar. 31, 2025	May 06, 2025
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2025
Document Transition Report	false
Entity File Number	001-38979
Entity Registrant Name	Acadian Asset Management Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-1121020
Entity Address, Address Line One	200 State Street, 13th Floor
Entity Address, City or Town	Boston,
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02109
City Area Code	617
Local Phone Number	369-7300
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		35,795,275
Entity Central Index Key	0001748824
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	Q1
Amendment Flag	false
Common Stock
Entity Information [Line Items]
Title of 12(b) Security	Common stock, par value $0.001 per share
Trading Symbol	AAMI
Security Exchange Name	NYSE
4.800% Notes due 2026
Entity Information [Line Items]
Title of 12(b) Security	4.800% Notes due 2026
Trading Symbol	AAMI 26
Security Exchange Name	NYSE