Introduction and Basis of Presentation	9 Months Ended
Sep. 30, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Introduction and Basis of Presentation	1. INTRODUCTION AND BASIS OF PRESENTATION MSCI Inc., together with its wholly-owned subsidiaries (the “Company” or “MSCI”), offers content, applications and services to support the needs of institutional investors throughout their investment processes. The Company’s flagship products are its global equity indexes, custom indexes, factor indexes and ESG indexes; its analytics products, including multi-factor models, pricing models, methodologies for performance attribution, models for statistical analysis, and tools for portfolio optimization, back testing and stress testing; its ESG research and ratings; and its real estate benchmarks, indexes, business intelligence and analytics. Income (loss) from discontinued operations, net of income taxes in the Unaudited Condensed Consolidated Statement of Income for the nine months ended September 30, 2015 represents the impact of an out-of-period income tax charge associated with tax obligations triggered upon the sale of Institutional Shareholder Services Inc., which was completed on April 30, 2014. Basis of Presentation and Use of Estimates These unaudited condensed consolidated financial statements include the accounts of MSCI Inc. and its subsidiaries and include all adjustments of a normal, recurring nature necessary to present fairly the financial condition as of September 30, 2016 and December 31, 2015, the results of operations and comprehensive income for the three and nine months ended September 30, 2016 and 2015 and cash flows for the nine months ended September 30, 2016 and 2015. The accompanying unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes included in MSCI’s Annual Report on Form 10-K for the year ended December 31, 2015. The unaudited condensed consolidated financial statement information as of December 31, 2015 has been derived from the 2015 audited consolidated financial statements. The results of operations for interim periods are not necessarily indicative of results for the entire year. The Company’s unaudited condensed consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). These accounting principles require the Company to make certain estimates and judgments that can affect the reported amounts of assets and liabilities as of the date of the unaudited condensed consolidated financial statements, as well as the reported amounts of revenue and expenses during the periods presented. Significant estimates and assumptions made by management include the deferral and recognition of revenue, research and development and software capitalization, the allowance for doubtful accounts, impairment of long-lived assets, accrued compensation, income taxes and other matters that affect the unaudited condensed consolidated financial statements and related disclosures. The Company believes that estimates used in the preparation of these unaudited condensed consolidated financial statements are reasonable; however, actual results could differ materially from these estimates. Intercompany balances and transactions are eliminated in consolidation. Concentrations No single customer represented 10.0% or more of the Company’s consolidated operating revenues for the nine months ended September 30, 2016, while BlackRock, Inc. accounted for 10.4% of the Company’s consolidated operating revenues for the nine months ended September 30, 2015. For the nine months ended September 30, 2016 and 2015, BlackRock, Inc. accounted for 17.1% and 19.5% of the Index segment operating revenues, respectively. No single customer represented 10.0% or more of revenues within the Analytics and All Other segments for the nine months ended September 30, 2016 and 2015.

1. INTRODUCTION AND BASIS OF PRESENTATION

MSCI Inc., together with its wholly-owned subsidiaries (the “Company” or “MSCI”), offers content, applications and services to support the needs of institutional investors throughout their investment processes. The Company’s flagship products are its global equity indexes, custom indexes, factor indexes and ESG indexes; its analytics products, including multi-factor models, pricing models, methodologies for performance attribution, models for statistical analysis, and tools for portfolio optimization, back testing and stress testing; its ESG research and ratings; and its real estate benchmarks, indexes, business intelligence and analytics.

Income (loss) from discontinued operations, net of income taxes in the Unaudited Condensed Consolidated Statement of Income for the nine months ended September 30, 2015 represents the impact of an out-of-period income tax charge associated with tax obligations triggered upon the sale of Institutional Shareholder Services Inc., which was completed on April 30, 2014.

Basis of Presentation and Use of Estimates

These unaudited condensed consolidated financial statements include the accounts of MSCI Inc. and its subsidiaries and include all adjustments of a normal, recurring nature necessary to present fairly the financial condition as of September 30, 2016 and December 31, 2015, the results of operations and comprehensive income for the three and nine months ended September 30, 2016 and 2015 and cash flows for the nine months ended September 30, 2016 and 2015. The accompanying unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes included in MSCI’s Annual Report on Form 10-K for the year ended December 31, 2015. The unaudited condensed consolidated financial statement information as of December 31, 2015 has been derived from the 2015 audited consolidated financial statements. The results of operations for interim periods are not necessarily indicative of results for the entire year.

The Company’s unaudited condensed consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). These accounting principles require the Company to make certain estimates and judgments that can affect the reported amounts of assets and liabilities as of the date of the unaudited condensed consolidated financial statements, as well as the reported amounts of revenue and expenses during the periods presented. Significant estimates and assumptions made by management include the deferral and recognition of revenue, research and development and software capitalization, the allowance for doubtful accounts, impairment of long-lived assets, accrued compensation, income taxes and other matters that affect the unaudited condensed consolidated financial statements and related disclosures. The Company believes that estimates used in the preparation of these unaudited condensed consolidated financial statements are reasonable; however, actual results could differ materially from these estimates. Intercompany balances and transactions are eliminated in consolidation.

Concentrations

No single customer represented 10.0% or more of the Company’s consolidated operating revenues for the nine months ended September 30, 2016, while BlackRock, Inc. accounted for 10.4% of the Company’s consolidated operating revenues for the nine months ended September 30, 2015. For the nine months ended September 30, 2016 and 2015, BlackRock, Inc. accounted for 17.1% and 19.5% of the Index segment operating revenues, respectively. No single customer represented 10.0% or more of revenues within the Analytics and All Other segments for the nine months ended September 30, 2016 and 2015.