Note 11 - Subsequent Events (Details Textual) - Subsequent Event [Member] - USD ($) $ in Millions	Apr. 26, 2017	Apr. 17, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options and Other than Options, Grants, Fair Value	$ 16.6
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Eliza Holding Group [Member]
Business Combination, Consideration Transferred		$ 172.0
Business Combination, Purchase Percent, Cash		75.00%
Business Combination, Purchase Percent, Revolving Credit Facility		25.00%

Represents the percentage of cash on hand used to purchase an acquisition.

No definition available.

Name:	hmsy_BusinessCombinationPurchasePercentCash
Namespace Prefix:	hmsy_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the percentage of the revolving credit facility used to purchase an acquisition.

+ References

No definition available.

+ Details

Name:	hmsy_BusinessCombinationPurchasePercentRevolvingCreditFacility
Namespace Prefix:	hmsy_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The fair value at grant date for nonvested equity awards, which includes stock options and restricted stock units granted.

+ References

No definition available.

+ Details

Name:	hmsy_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndOtherThanOptionsGrantsFairValue
Namespace Prefix:	hmsy_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6578-128477

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6613-128477

+ Details

Name:	us-gaap_BusinessCombinationConsiderationTransferred1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=hmsy_ElizaHoldingGroupMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: