Overview and significant Accounting Policies (Details 5) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
Sep. 30, 2016	Dec. 31, 2018	Dec. 31, 2017
Insurance
Deductible for individual healthcare claims		$ 0.3
Deductible for workers' compensation	$ 0.5
Deductible for general liability claims		0.3
Self insurance reserve		$ 2.7	$ 3.5

Represents the amount deductible during the period for individual healthcare claims.

No definition available.

Name:	hhs_DeductibleForIndividualHealthCareClaims
Namespace Prefix:	hhs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the amount deductible during the period for workers' compensation.

+ References

No definition available.

+ Details

Name:	hhs_DeductibleForWorkersCompensation
Namespace Prefix:	hhs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the amount deductible during the period for general liability claims.

+ References

No definition available.

+ Details

Name:	hhs_DeductibleforGeneralLiabilityClaims
Namespace Prefix:	hhs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_InsuranceAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Carrying amount (including both current and noncurrent portions) of accrued known and estimated losses incurred as of the balance sheet date for which no insurance coverage exists, and for which a claim has been made or is probable of being asserted, typically arising from workmen's compensation-type of incidents and personal injury to nonemployees from accidents on the entity's property.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.24)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_SelfInsuranceReserve
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant