v3.26.1
Cover Page - shares
 6 Months Ended
Jun. 30, 2026
Aug. 05, 2026
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Jun. 30, 2026  
Document Transition Report false  
Entity File Number 001-39716  
Entity Registrant Name GCM Grosvenor Inc.  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 85-2226287  
Entity Address, Address Line One 900 North Michigan Avenue, Suite 1100  
Entity Address, City or Town Chicago  
Entity Address, State or Province IL  
Entity Address, Postal Zip Code 60611  
City Area Code 312  
Local Phone Number 506-6500  
Title of 12(b) Security Class A common stock, $0.0001 par value per share  
Trading Symbol GCMG  
Security Exchange Name NASDAQ  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Amendment Flag false  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q2  
Current Fiscal Year End Date --12-31  
Entity Central Index Key 0001819796  
Class A common stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   61,126,269
Class C common stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   141,665,831