Business and Basis of Presentation	6 Months Ended
Jun. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business and Basis of Presentation	Business and Basis of Presentation Business. Gartner, Inc. is a global information technology research and advisory company with its headquarters in Stamford, Connecticut. Gartner delivers its products and services globally through three business segments: Research, Consulting, and Events. When used in these notes, the terms “Gartner,” “Company,” “we,” “us,” or “our” refer to Gartner, Inc. and its consolidated subsidiaries. Basis of presentation. The accompanying interim condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“U.S. GAAP”), as defined in the Financial Accounting Standards Board ("FASB") Accounting Standards Codification (“ASC”) Topic 270 for interim financial information and with the applicable instructions of the U.S. Securities & Exchange Commission (“SEC”) Rule 10-01 of Regulation S-X on Form 10-Q and should be read in conjunction with the consolidated financial statements and related notes of the Company filed in its Annual Report on Form 10-K for the year ended December 31, 2014. The fiscal year of Gartner is the twelve-month calendar period from January 1 through December 31. In the opinion of management, all normal recurring accruals and adjustments considered necessary for a fair presentation of financial position, results of operations and cash flows at the dates and for the periods presented herein have been included. The results of operations for the three and six months ended June 30, 2015 may not be indicative of the results of operations for the remainder of 2015. Principles of consolidation. The accompanying interim condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All significant intercompany transactions and balances have been eliminated. Use of estimates. The preparation of the accompanying interim condensed consolidated financial statements requires management to make estimates and assumptions about future events. These estimates and the underlying assumptions affect the amounts of assets and liabilities reported, disclosures about contingent assets and liabilities, and reported amounts of revenues and expenses. Such estimates include the valuation of fees receivable, goodwill, intangible assets, and other long-lived assets, as well as tax accruals and other liabilities. In addition, estimates are used in revenue recognition, income tax expense, performance-based compensation charges, depreciation and amortization, and the allowance for losses on fees receivable. Management believes its use of estimates in these interim condensed consolidated financial statements to be reasonable. Management continually evaluates and revises its estimates using historical experience and other factors, including the general economic environment and actions it may take in the future. Management adjusts these estimates when facts and circumstances dictate. However, these estimates may involve significant uncertainties and judgments and cannot be determined with precision. In addition, these estimates are based on management’s best judgment at a point in time. As a result, differences between our estimates and actual results could be material and would be reflected in the Company’s financial statements in future periods. Adoption of new accounting standard. On January 1, 2015, the Company adopted FASB Accounting Standards Update No. 2014-08, Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity ("ASU 2014-08"), which changes the criteria for determining which disposal transactions can be presented as discontinued operations and modifies related disclosure requirements. Under the new guidance, a discontinued operation is defined as a disposal of a component or group of components that is disposed of or is classified as held for sale and represents a strategic shift that has (or will have) a major effect on an entity’s operations and financial results. The adoption of the rule did not have an impact on the Company's condensed consolidated financial statements contained in this report. Acquisitions. In July 2015 the Company acquired Nubera eBusiness S.L. ("Nubera"), a Barcelona-based business whose primary asset is GetApp, a discovery and review platform that helps organizations discover, compare and choose the right business software and applications for their needs. Nubera was acquired by a foreign subsidiary of the Company with cash held overseas. The Company completed three acquisitions in the six months ended June 30, 2014. Certain charges related to these acquisitions are presented in the Acquisition and Integration Charges line on the Condensed Consolidated Statements of Operations. These charges include amounts accrued for payments contingent on the achievement of certain employment conditions, legal, consulting, and severance costs. The Company paid $9.2 million of the amount accrued for the achievement of certain employment conditions in the six months ended June 30, 2015.

Business and Basis of Presentation

Business. Gartner, Inc. is a global information technology research and advisory company with its headquarters in Stamford, Connecticut. Gartner delivers its products and services globally through three business segments: Research, Consulting, and Events. When used in these notes, the terms “Gartner,” “Company,” “we,” “us,” or “our” refer to Gartner, Inc. and its consolidated subsidiaries.

Basis of presentation. The accompanying interim condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“U.S. GAAP”), as defined in the Financial Accounting Standards Board ("FASB") Accounting Standards Codification (“ASC”) Topic 270 for interim financial information and with the applicable instructions of the U.S. Securities & Exchange Commission (“SEC”) Rule 10-01 of Regulation S-X on Form 10-Q and should be read in conjunction with the consolidated financial statements and related notes of the Company filed in its Annual Report on Form 10-K for the year ended December 31, 2014. The fiscal year of Gartner is the twelve-month calendar period from January 1 through December 31. In the opinion of management, all normal recurring accruals and adjustments considered necessary for a fair presentation of financial position, results of operations and cash flows at the dates and for the periods presented herein have been included. The results of operations for the three and six months ended June 30, 2015 may not be indicative of the results of operations for the remainder of 2015.

Principles of consolidation. The accompanying interim condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All significant intercompany transactions and balances have been eliminated.

Use of estimates. The preparation of the accompanying interim condensed consolidated financial statements requires management to make estimates and assumptions about future events. These estimates and the underlying assumptions affect the amounts of assets and liabilities reported, disclosures about contingent assets and liabilities, and reported amounts of revenues and expenses. Such estimates include the valuation of fees receivable, goodwill, intangible assets, and other long-lived assets, as well as tax accruals and other liabilities. In addition, estimates are used in revenue recognition, income tax expense, performance-based compensation charges, depreciation and amortization, and the allowance for losses on fees receivable. Management believes its use of estimates in these interim condensed consolidated financial statements to be reasonable.

Management continually evaluates and revises its estimates using historical experience and other factors, including the general economic environment and actions it may take in the future. Management adjusts these estimates when facts and circumstances dictate. However, these estimates may involve significant uncertainties and judgments and cannot be determined with precision. In addition, these estimates are based on management’s best judgment at a point in time. As a result, differences between our estimates and actual results could be material and would be reflected in the Company’s financial statements in future periods.

Adoption of new accounting standard. On January 1, 2015, the Company adopted FASB Accounting Standards Update No. 2014-08, Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity ("ASU 2014-08"), which changes the criteria for determining which disposal transactions can be presented as discontinued operations and modifies related disclosure requirements. Under the new guidance, a discontinued operation is defined as a disposal of a component or group of components that is disposed of or is classified as held for sale and represents a strategic shift that has (or will have) a major effect on an entity’s operations and financial results. The adoption of the rule did not have an impact on the Company's condensed consolidated financial statements contained in this report.

Acquisitions. In July 2015 the Company acquired Nubera eBusiness S.L. ("Nubera"), a Barcelona-based business whose primary asset is GetApp, a discovery and review platform that helps organizations discover, compare and choose the right business software and applications for their needs. Nubera was acquired by a foreign subsidiary of the Company with cash held overseas.

The Company completed three acquisitions in the six months ended June 30, 2014. Certain charges related to these acquisitions are presented in the Acquisition and Integration Charges line on the Condensed Consolidated Statements of Operations. These charges include amounts accrued for payments contingent on the achievement of certain employment conditions, legal, consulting, and severance costs. The Company paid $9.2 million of the amount accrued for the achievement of certain employment conditions in the six months ended June 30, 2015.