Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2023	Jul. 31, 2023
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2023
Document Transition Report	false
Entity File Number	001-38980
Entity Registrant Name	ASSETMARK FINANCIAL HOLDINGS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	30-0774039
Entity Address, Address Line One	1655 Grant Street
Entity Address, Address Line Two	10th Floor
Entity Address, City or Town	Concord
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94520
City Area Code	925
Local Phone Number	521-2200
Title of 12(b) Security	Common stock, par value $0.001 per share
Trading Symbol	AMK
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		74,262,033
Entity Central Index Key	0001591587
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q2
Amendment Flag	false
Current Fiscal Year End Date	--12-31