Subsequent Events	12 Months Ended
Dec. 31, 2017
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Amendment to Credit Facility On January 9, 2018, we entered into an amendment to the Texas Capital Credit Facility that increased the borrowing capacity to $22 million and extended the maturity by one year to April 17, 2020. The Texas Capital Credit Facility remains secured by substantially all of our assets and continues to be guaranteed by HHS Guaranty, an entity formed by certain members of the descendants of one of our founders. For additional information regarding the amendment to the Texas Capital Credit Facility refer to Note C, Long-Term Debt. Securities Purchase Agreement On January 23, 2018, we entered into a Securities Purchase Agreement with Wipro, LLC. The agreement consisted of a $9.9 million investment in exchange for 9,926 shares of Series A Preferred Stock. Dividends on the Series A Preferred Stock are accrued at a rate of 5.0% per year or the rate that cash dividends were paid in respect to shares of common stock if such rate is greater than 5.0%. The aggregate shares issued under the Securities Purchase Agreements are convertible into 16% of our common stock on a pre-closing basis, priced at $9.91 per share of common stock. Along with customary protective provisions, Wipro, LLC will be able to designate an observer or director to the Board. We intend to use the proceeds for general corporate purposes including for working capital purposes. Since 2016, Wipro, LLC has provided a variety of technology-related service to the Company, including database and software development, database support and analytics, IT infrastructure support, and digital campaign management. Transactions with Wipro, LLC will be classified and disclosed in 2018 as related party transactions in accordance with ASC 850, Related Party Disclosures, and in accordance with the SEC's Regulation S-X Rule 4-08(k), as applicable. Reverse Stock Split On January 31, 2018, we executed a 1-for-10 reverse stock split. Pursuant to the reverse stock split, every 10 pre-split shares were exchanged for one post-split share of Harte Hanks' Common Stock. For additional information regarding the Reverse Stock Split refer to Note A, Significant Accounting Policies. Sale of 3Q Digital On February 28, 2018, we sold our 3Q Digital, Inc. subsidiary to an entity owned by certain former owners of the 3Q Digital business. Consideration for the sale included $5.0 million in cash proceeds, subject to certain working capital adjustments, and up to $5.0 million in additional consideration if the 3Q Digital business is sold again. The $35.0 million contingent consideration obligation of the company that related to Harte Hanks' acquisition of 3Q Digital in 2015 was assigned to the buyer, therefore relieving Harte Hanks of the obligation.

Subsequent Events

Amendment to Credit Facility

On January 9, 2018, we entered into an amendment to the Texas Capital Credit Facility that increased the borrowing capacity to $22 million and extended the maturity by one year to April 17, 2020. The Texas Capital Credit Facility remains secured by substantially all of our assets and continues to be guaranteed by HHS Guaranty, an entity formed by certain members of the descendants of one of our founders. For additional information regarding the amendment to the Texas Capital Credit Facility refer to Note C, Long-Term Debt.

Securities Purchase Agreement

On January 23, 2018, we entered into a Securities Purchase Agreement with Wipro, LLC. The agreement consisted of a $9.9 million investment in exchange for 9,926 shares of Series A Preferred Stock. Dividends on the Series A Preferred Stock are accrued at a rate of 5.0% per year or the rate that cash dividends were paid in respect to shares of common stock if such rate is greater than 5.0%. The aggregate shares issued under the Securities Purchase Agreements are convertible into 16% of our common stock on a pre-closing basis, priced at $9.91 per share of common stock.

Along with customary protective provisions, Wipro, LLC will be able to designate an observer or director to the Board. We intend to use the proceeds for general corporate purposes including for working capital purposes.

Since 2016, Wipro, LLC has provided a variety of technology-related service to the Company, including database and software development, database support and analytics, IT infrastructure support, and digital campaign management. Transactions with Wipro, LLC will be classified and disclosed in 2018 as related party transactions in accordance with ASC 850, Related Party Disclosures, and in accordance with the SEC's Regulation S-X Rule 4-08(k), as applicable.

Reverse Stock Split

On January 31, 2018, we executed a 1-for-10 reverse stock split. Pursuant to the reverse stock split, every 10 pre-split shares were exchanged for one post-split share of Harte Hanks' Common Stock. For additional information regarding the Reverse Stock Split refer to Note A, Significant Accounting Policies.

Sale of 3Q Digital

On February 28, 2018, we sold our 3Q Digital, Inc. subsidiary to an entity owned by certain former owners of the 3Q Digital business. Consideration for the sale included $5.0 million in cash proceeds, subject to certain working capital adjustments, and up to $5.0 million in additional consideration if the 3Q Digital business is sold again. The $35.0 million contingent consideration obligation of the company that related to Harte Hanks' acquisition of 3Q Digital in 2015 was assigned to the buyer, therefore relieving Harte Hanks of the obligation.