Recent Developments	9 Months Ended
Sep. 30, 2014
Subsequent Events [Abstract]
Recent Developments	On November 1, 2014, Sapient entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Publicis Groupe S.A., a French société anonyme (“Publicis Groupe ”), and 1926 Merger Sub Inc., a Delaware corporation and a wholly owned subsidiary of Publicis Groupe (“Merger Sub”). Under the Merger Agreement, Publicis Groupe will cause Merger Sub to commence a cash tender offer (the “Offer”) within 10 business days following the date of the Merger Agreement, for all of Sapient’s outstanding shares of common stock, par value $0.01 per share (the “Shares”), at a purchase price of $25.00 per Share, net to the seller in cash, without interest, subject to any required withholding of taxes. The Offer will remain open for a minimum of 20 business days from the date of commencement. The transaction was unanimously approved by the Board of Directors of Sapient and the Management and Supervisory Boards of Publicis Groupe. The obligation of Merger Sub to purchase the Shares in the Offer is subject to certain closing conditions, including the Shares having been validly tendered and not withdrawn representing at least a majority of the total number of Shares then-outstanding, expiration or termination of applicable waiting periods under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and the antitrust, competition and trade regulation laws of Germany, the conclusion or termination of review by the Committee on Foreign Investment in the United States and certain other regulatory approvals. The transaction is expected to close in the first quarter of 2015, although there can be no assurance the transaction will close within the expected timeframe or at all. If the Merger Agreement is terminated under certain circumstances, Sapient may be obligated to pay Publicis Groupe a termination fee of $125.0 million. For further information regarding the transaction and the Merger Agreement, please refer to the Current Report on Form 8-K filed on November 3, 2014, with which the Merger Agreement is filed as Exhibit 2.1.

On November 1, 2014, Sapient entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Publicis Groupe S.A., a French société anonyme (“Publicis Groupe ”), and 1926 Merger Sub Inc., a Delaware corporation and a wholly owned subsidiary of Publicis Groupe (“Merger Sub”). Under the Merger Agreement, Publicis Groupe will cause Merger Sub to commence a cash tender offer (the “Offer”) within 10 business days following the date of the Merger Agreement, for all of Sapient’s outstanding shares of common stock, par value $0.01 per share (the “Shares”), at a purchase price of $25.00 per Share, net to the seller in cash, without interest, subject to any required withholding of taxes. The Offer will remain open for a minimum of 20 business days from the date of commencement. The transaction was unanimously approved by the Board of Directors of Sapient and the Management and Supervisory Boards of Publicis Groupe. The obligation of Merger Sub to purchase the Shares in the Offer is subject to certain closing conditions, including the Shares having been validly tendered and not withdrawn representing at least a majority of the total number of Shares then-outstanding, expiration or termination of applicable waiting periods under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and the antitrust, competition and trade regulation laws of Germany, the conclusion or termination of review by the Committee on Foreign Investment in the United States and certain other regulatory approvals. The transaction is expected to close in the first quarter of 2015, although there can be no assurance the transaction will close within the expected timeframe or at all. If the Merger Agreement is terminated under certain circumstances, Sapient may be obligated to pay Publicis Groupe a termination fee of $125.0 million.

For further information regarding the transaction and the Merger Agreement, please refer to the Current Report on Form 8-K filed on November 3, 2014, with which the Merger Agreement is filed as Exhibit 2.1.