Document and Entity Information - USD ($)
12 Months Ended
Dec. 31, 2017
Jan. 31, 2018
Jun. 30, 2017
Document and Entity Information      
Entity Registrant Name HARTE HANKS INC    
Entity Central Index Key 0000045919    
Document Type 10-K    
Document Period End Date Dec. 31, 2017    
Amendment Flag false    
Current Fiscal Year End Date --12-31    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status No    
Entity Filer Category Accelerated Filer    
Entity Public Float     $ 50,200,128
Entity Common Stock, Shares Outstanding   6,217,586  
Document Fiscal Year Focus 2017    
Document Fiscal Period Focus FY