COVER PAGE - shares	6 Months Ended
	Jun. 30, 2020	Aug. 03, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2020
Document Transition Report	false
Entity File Number	000-50194
Entity Registrant Name	HMS HOLDINGS CORP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	11-3656261
Entity Address, Address Line One	5615 High Point Drive
Entity Address, City or Town	Irving,
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	75038
City Area Code	214
Local Phone Number	453-3000
Title of 12(b) Security	Common Stock $0.01 par value
Trading Symbol	HMSY
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 Common Stock, Shares Outstanding (in shares)		88,517,819
Entity Central Index Key	0001196501
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Amendment Flag	false