Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2021	Mar. 31, 2022	Jun. 30, 2021
Document Information [Line Items]
Entity Central Index Key	0000045919
Entity Registrant Name	HARTE HANKS INC
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2021
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Document Transition Report	false
Entity File Number	001-07120
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	74-1677284
Entity Address, Address Line One	2 Executive Drive
Entity Address, City or Town	Chelmsford
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	01824
City Area Code	512
Local Phone Number	434-1100
Title of 12(b) Security	Common Stock
Trading Symbol	HHS
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 30,396,333
Entity Common Stock, Shares Outstanding		7,002,528
Auditor Name	Baker Tilly US, LLP
Auditor Location	Tewksbury, Massachusetts
Auditor Firm ID	23