Business and Basis of Presentation	6 Months Ended
Jun. 30, 2016
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, 2015. 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, 2016 may not be indicative of the results of operations for the remainder of 2016 or beyond. 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. Management believes its use of estimates in these interim condensed consolidated financial statements to be reasonable. Management continuously 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 consolidated financial statements in future periods. Accounting standards issued but not yet adopted. The FASB has issued several accounting standards that have not yet become effective and that may impact the Company’s consolidated financial statements or related disclosures in future periods. These standards and their potential impact are discussed below: Financial Instrument Credit Losses—In June 2016, the FASB issued Accounting Standards Update (“ASU”) No. 2016-13, "Financial Instruments—Credit Losses" ("ASU No. 2016-13"). ASU No. 2016-13 amends the current financial instrument impairment model by requiring entities to use a forward-looking approach based on expected losses to estimate credit losses on certain types of financial instruments, including trade receivables. ASU No. 2016-13 is effective for Gartner on January 1, 2020, with early adoption permitted. We are currently evaluating the potential impact of ASU No. 2016-13 on the Company's consolidated financial statements. Stock-Based Compensation—In March 2016, the FASB issued ASU No. 2016-09, "Improvements to Employee Share-Based Payment Accounting" ("ASU No. 2016-09"). ASU No. 2016-09 modifies several aspects of the accounting for employee share-based payment awards, to include the accounting for award forfeitures, the amount of employer tax withholding on awards that vest or settle, and the financial statement impact of excess tax benefits or deficiencies. ASU No. 2016-09 also modifies the statement of cash flows presentation for certain components of share-based payment awards. The provisions of the new rule will be effective for Gartner on January 1, 2017, with early adoption permitted. We are currently evaluating the potential impact of ASU No. 2016-09 on the Company's consolidated financial statements. Leases — In February 2016, the FASB issued ASU No. 2016-02, "Leases" ("ASU No. 2016-02") which will require significant changes in the accounting and disclosure of lease arrangements. Among the significant changes required by ASU No. 2016-02 is that almost all lease obligations will be recorded on the balance sheet as a liability, along with a corresponding right of use asset. Currently under U.S. GAAP, lease arrangements that meet certain criteria are considered operating leases and are not recorded on the balance sheet. ASU No. 2016-02 also requires certain key information about leasing arrangements be disclosed. ASU No. 2016-02 will be effective for Gartner on January 1, 2019. We are currently evaluating the impact of ASU No. 2016-02 on the Company's consolidated financial statements. Revenue — In May 2014, the FASB issued ASU No. 2014-09, "Revenue from Contracts with Customers" ("ASU No. 2014-09"). ASU No. 2014-09 and related amendments require changes in revenue recognition policies as well as require enhanced disclosures. ASU No. 2014-09 is intended to clarify the principles for recognizing revenue by removing inconsistencies and weaknesses in existing revenue recognition rules; provide a more robust framework for addressing revenue recognition issues; improve comparability of revenue recognition practices across entities, industries, jurisdictions and capital markets; and provide more useful information to users of financial statements through improved revenue disclosures. ASU No. 2014-09 will be effective for Gartner on January 1, 2018, and the Company expects to complete its assessment of the estimated impact of ASU No. 2014-09 on its consolidated financial statements by the end of 2016. The FASB also continues to work on a number of other significant accounting standards which if issued could materially impact the Company's accounting policies and disclosures in future periods. However, since these standards have not yet been issued, the effective dates and potential impact are unknown. Acquisitions. The Company accounts for business acquisitions in accordance with the acquisition method of accounting as prescribed by FASB ASC Topic 805, Business Combinations. The acquisition method of accounting requires the Company to record the net assets and liabilities acquired based on their estimated fair values as of the acquisition date, with any excess of the consideration transferred over the estimated fair value of the net assets acquired, including identifiable intangible assets, to be recorded to goodwill. Under the acquisition method, the operating results of acquired companies are included in the Company's consolidated financial statements beginning on the date of acquisition. On June 28, 2016, the Company acquired 100% of the outstanding capital stock of Newco 5CL Limited (which operates under the trade name "SCM World"), a privately-held firm based in London with 60 employees. SCM World is a leading cross-industry peer network and learning community providing subscription-based research and conferences for supply chain executives. The Company paid $34.2 million of its cash held overseas at close and may also be required to pay up to an additional $15.0 million in cash for potential earn-out payments tied to the performance of SCM World through December 31, 2016. Any estimated earn-out payments determined as of the acquisition date will be recorded as part of the cost of the acquisition and will be adjusted to fair value at each reporting period through income until the amount is settled. The Company may also be required to pay up to an additional $8.0 million in cash contingent on the achievement of certain employment conditions by several key employees (who are also former shareholders) of SCM World, which will be recognized as compensation expense. The Company recorded $37.0 million of goodwill and amortizable intangible assets for SCM World (see Note 5—Goodwill and Intangible Assets for additional information) and $2.8 million of liabilities on a net basis on the acquisition date. These amounts and the overall allocation of the purchase price is preliminary. The Company anticipates completing the valuation of the acquired assets and liabilities and the allocation of the purchase price in the third quarter of 2016. The operating results and the related goodwill will likely be reported as part of the Company's Research segment and goodwill resulting from the acquisition will not be deductible for tax purposes. Had the Company acquired SCM World in a prior period, the impact to the Company's results would not have been material, and as a result pro forma financial information for prior periods has not been provided. The Company recognized $8.0 million and $3.7 million of acquisition and integration charges in the three months ended June 30, 2016 and 2015, respectively, and $16.4 million and $8.8 million of acquisition and integration charges in the six months ended June 30, 2016 and 2015, respectively. These charges are classified in Acquisition and integration charges in the Condensed Consolidated Statements of Operations and include amounts accrued for payments contingent on the achievement of certain employment conditions, legal, consulting, and severance costs. The Company paid $22.7 million in cash during the six months ended June 30, 2016 for the achievement of certain employment conditions related to an acquisition completed in 2014, of which $13.6 million was paid from escrow and $9.1 million was paid from existing Company cash. On a net basis, and for cash flow reporting purposes, the Company paid $28.9 million in cash at close for SCM World, which represents the gross cash paid of $34.2 million less cash held by SCM World at the acquisition date. During the six months ended June 30, 2016, the Company also paid $1.0 million for a working capital settlement related to a 2015 acquisition.

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, 2015. 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, 2016 may not be indicative of the results of operations for the remainder of 2016 or beyond.

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. Management believes its use of estimates in these interim condensed consolidated financial statements to be reasonable.

Management continuously 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 consolidated financial statements in future periods.

Accounting standards issued but not yet adopted. The FASB has issued several accounting standards that have not yet become effective and that may impact the Company’s consolidated financial statements or related disclosures in future periods. These standards and their potential impact are discussed below:

Financial Instrument Credit Losses—In June 2016, the FASB issued Accounting Standards Update (“ASU”) No. 2016-13, "Financial Instruments—Credit Losses" ("ASU No. 2016-13"). ASU No. 2016-13 amends the current financial instrument impairment model by requiring entities to use a forward-looking approach based on expected losses to estimate credit losses on certain types of financial instruments, including trade receivables. ASU No. 2016-13 is effective for Gartner on January 1, 2020, with early adoption permitted. We are currently evaluating the potential impact of ASU No. 2016-13 on the Company's consolidated financial statements.

Stock-Based Compensation—In March 2016, the FASB issued ASU No. 2016-09, "Improvements to Employee Share-Based Payment Accounting" ("ASU No. 2016-09"). ASU No. 2016-09 modifies several aspects of the accounting for employee share-based payment awards, to include the accounting for award forfeitures, the amount of employer tax withholding on awards that vest or settle, and the financial statement impact of excess tax benefits or deficiencies. ASU No. 2016-09 also modifies the statement of cash flows presentation for certain components of share-based payment awards. The provisions of the new rule will be effective for Gartner on January 1, 2017, with early adoption permitted. We are currently evaluating the potential impact of ASU No. 2016-09 on the Company's consolidated financial statements.

Leases — In February 2016, the FASB issued ASU No. 2016-02, "Leases" ("ASU No. 2016-02") which will require significant changes in the accounting and disclosure of lease arrangements. Among the significant changes required by ASU No. 2016-02 is that almost all lease obligations will be recorded on the balance sheet as a liability, along with a corresponding right of use asset. Currently under U.S. GAAP, lease arrangements that meet certain criteria are considered operating leases and are not recorded on the balance sheet. ASU No. 2016-02 also requires certain key information about leasing arrangements be disclosed. ASU No. 2016-02 will be effective for Gartner on January 1, 2019. We are currently evaluating the impact of ASU No. 2016-02 on the Company's consolidated financial statements.

Revenue — In May 2014, the FASB issued ASU No. 2014-09, "Revenue from Contracts with Customers" ("ASU No. 2014-09"). ASU No. 2014-09 and related amendments require changes in revenue recognition policies as well as require enhanced disclosures. ASU No. 2014-09 is intended to clarify the principles for recognizing revenue by removing inconsistencies and weaknesses in existing revenue recognition rules; provide a more robust framework for addressing revenue recognition issues; improve comparability of revenue recognition practices across entities, industries, jurisdictions and capital markets; and provide more useful information to users of financial statements through improved revenue disclosures. ASU No. 2014-09 will be effective for Gartner on January 1, 2018, and the Company expects to complete its assessment of the estimated impact of ASU No. 2014-09 on its consolidated financial statements by the end of 2016.

The FASB also continues to work on a number of other significant accounting standards which if issued could materially impact the Company's accounting policies and disclosures in future periods. However, since these standards have not yet been issued, the effective dates and potential impact are unknown.

Acquisitions. The Company accounts for business acquisitions in accordance with the acquisition method of accounting as prescribed by FASB ASC Topic 805, Business Combinations. The acquisition method of accounting requires the Company to record the net assets and liabilities acquired based on their estimated fair values as of the acquisition date, with any excess of the consideration transferred over the estimated fair value of the net assets acquired, including identifiable intangible assets, to be recorded to goodwill. Under the acquisition method, the operating results of acquired companies are included in the Company's consolidated financial statements beginning on the date of acquisition.

On June 28, 2016, the Company acquired 100% of the outstanding capital stock of Newco 5CL Limited (which operates under the trade name "SCM World"), a privately-held firm based in London with 60 employees. SCM World is a leading cross-industry peer network and learning community providing subscription-based research and conferences for supply chain executives. The Company paid $34.2 million of its cash held overseas at close and may also be required to pay up to an additional $15.0 million in cash for potential earn-out payments tied to the performance of SCM World through December 31, 2016. Any estimated earn-out payments determined as of the acquisition date will be recorded as part of the cost of the acquisition and will be adjusted to fair value at each reporting period through income until the amount is settled.

The Company may also be required to pay up to an additional $8.0 million in cash contingent on the achievement of certain employment conditions by several key employees (who are also former shareholders) of SCM World, which will be recognized as compensation expense. The Company recorded $37.0 million of goodwill and amortizable intangible assets for SCM World (see Note 5—Goodwill and Intangible Assets for additional information) and $2.8 million of liabilities on a net basis on the acquisition date. These amounts and the overall allocation of the purchase price is preliminary. The Company anticipates completing the valuation of the acquired assets and liabilities and the allocation of the purchase price in the third quarter of 2016. The operating results and the related goodwill will likely be reported as part of the Company's Research segment and goodwill resulting from the acquisition will not be deductible for tax purposes. Had the Company acquired SCM World in a prior period, the impact to the Company's results would not have been material, and as a result pro forma financial information for prior periods has not been provided.

The Company recognized $8.0 million and $3.7 million of acquisition and integration charges in the three months ended June 30, 2016 and 2015, respectively, and $16.4 million and $8.8 million of acquisition and integration charges in the six months ended June 30, 2016 and 2015, respectively. These charges are classified in Acquisition and integration charges in the Condensed Consolidated Statements of Operations and include amounts accrued for payments contingent on the achievement of certain employment conditions, legal, consulting, and severance costs. The Company paid $22.7 million in cash during the six months ended June 30, 2016 for the achievement of certain employment conditions related to an acquisition completed in 2014, of which $13.6 million was paid from escrow and $9.1 million was paid from existing Company cash. On a net basis, and for cash flow reporting purposes, the Company paid $28.9 million in cash at close for SCM World, which represents the gross cash paid of $34.2 million less cash held by SCM World at the acquisition date. During the six months ended June 30, 2016, the Company also paid $1.0 million for a working capital settlement related to a 2015 acquisition.