v3.8.0.1
Document And Entity Information - shares
3 Months Ended
Mar. 31, 2018
Apr. 27, 2018
Document Information [Line Items]    
Entity Registrant Name HMS HOLDINGS CORP  
Entity Central Index Key 0001196501  
Trading Symbol hmsy  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Entity Current Reporting Status Yes  
Entity Voluntary Filers No  
Entity Well-known Seasoned Issuer Yes  
Entity Common Stock, Shares Outstanding (in shares)   83,216,661
Document Type 10-Q  
Document Period End Date Mar. 31, 2018  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q1  
Amendment Flag false