v3.26.1
Cover Page - shares
 3 Months Ended
Jun. 30, 2026
Aug. 04, 2026
Entity 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 001-39510  
Entity Registrant Name STEPSTONE GROUP INC.  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 84-3868757  
Entity Address, Address Line One 277 Park Avenue  
Entity Address, Address Line Two 45th Floor  
Entity Address, City or Town New York  
Entity Address, State or Province NY  
Entity Address, Postal Zip Code 10172  
City Area Code 212  
Local Phone Number 351-6100  
Title of 12(b) Security Class A Common Stock, $0.001 par value per share  
Trading Symbol STEP  
Security Exchange Name NASDAQ  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Central Index Key 0001796022  
Current Fiscal Year End Date --03-31  
Document Fiscal Year Focus 2027  
Document Fiscal Period Focus Q1  
Amendment Flag false  
Class A Common Stock    
Entity Information [Line Items]    
Entity Common Stock, Shares Outstanding   82,288,907
Class B Common Stock    
Entity Information [Line Items]    
Entity Common Stock, Shares Outstanding   38,387,761