Note 7 - Estimated Liability for Appeals (Details Textual) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Estimated Liability for Appeals	$ 30,754	$ 30,755
Estimated Liability for Appeals, Amount Adjudicated	18,800	17,300
Estimated Liability for Appeals, Amount Probable of Being Returned	9,800	11,100
Estimated Liability for Appeals, Commercial Customers Claim Findings, Adjudicated in Favor of Providers	$ 2,200	$ 2,400

Represents the portion of the estimated liability for appeals attributable to commercial customers claim findings which have been adjudicated in favor of providers and the Company’s estimate of the potential amount of commercial customers repayments that are probable of being adjudicated in favor of providers following a successful appeal.

No definition available.

Name:	hmsy_EstimatedLiabilityForAppealsCommercialCustomersClaimFindingsAdjudicatedInFavorOfProviders
Namespace Prefix:	hmsy_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant