Summary Of Significant Accounting Policies (Policy)	12 Months Ended
Summary Of Significant Accounting Policies (Policy)	Aug. 31, 2011
Summary Of Significant Accounting Policies [Abstract]
Basis Of Presentation	Basis of Presentation The accompanying consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany activity and balances have been eliminated from the consolidated financial statements. Certain reclassifications have been made to amounts for prior years in order to conform to the current year's presentation. The presentation of prior year segment operating profit for each of the Company's reportable segments in Note 6 to the consolidated financial statements has been adjusted to conform to the current year's presentation. This change reflects an allocation of expenses incurred in FactSet's content collection operations located in India and the Philippines, to each of the Company's reportable segments based on a percentage of revenues. These reclassifications between the U.S., Europe and Asia Pacific reportable segments had no effect on the Company's previously consolidated operating income, net income or stockholders' equity. FactSet has performed an evaluation of subsequent events occurring subsequent to the end of the Company's fiscal 2011 fourth quarter and through October 31, 2011, the date the consolidated financial statements were issued based on the accounting guidance for subsequent events.
Basis Of Financial Statements And Use Of Estimates	Basis of Financial Statements and Use of Estimates The Company's consolidated financial statements are prepared in accordance with U.S. generally accepted accounting principles. The preparation of consolidated financial statements and related disclosures in conformity with accounting principles generally accepted in the U.S. requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates have been made in areas that include receivable reserves, valuation of goodwill, useful lives and valuation of fixed and intangible assets, accrued compensation, income and other taxes, stock-based compensation and allocation of purchase price to assets and liabilities acquired. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Actual results could differ from those estimates.
Revenue Recognition	Revenue Recognition The Company's revenues are derived from month-to-month subscriptions to services such as workstations (also referred to as users), content and applications. Primarily all clients are invoiced monthly to reflect the actual services provided. The remaining clients are invoiced quarterly, annually or biannually in advance. Subscription revenue is earned each month as the service is rendered to clients on a monthly basis. FactSet recognizes revenue when the client subscribes to FactSet services, the service has been rendered and earned during the month, the amount of the subscription is fixed and determinable based on established rates quoted on an annualized basis and collectability is reasonably assured. A provision for billing adjustments and cancellation of services is estimated and accounted for as a reduction of revenue, with a corresponding reduction to accounts receivable.
Cost Of Services	Cost of Services Cost of services is composed of cash and stock-based compensation for Company employees within the content collection, consulting, product development, software and systems engineering groups in addition to data costs, amortization of identifiable intangible assets, computer maintenance and depreciation expenses and client-related communication costs.
Selling, General And Administrative	Selling, General and Administrative Selling, general and administrative expenses include cash and stock-based compensation for the sales and various other support and administrative departments, travel and entertainment expenses, marketing costs, rent, amortization of leasehold improvements, depreciation of furniture and fixtures, office expenses, professional fees and other miscellaneous expenses.
Earnings Per Share	Earnings per Share Basic earnings per share is computed by dividing net income by the number of weighted average common shares outstanding during the period. Diluted earnings per share is computed by dividing net income by the number of weighted average common shares outstanding during the period increased by the dilutive effect of potential common shares outstanding during the period. The number of potential common shares outstanding has been determined in accordance with the treasury stock method to the extent they are dilutive. Common share equivalents consist of common shares issuable upon the exercise of outstanding share-based compensation awards, including employee stock options and restricted stock. Under the treasury stock method, the exercise price paid by the optionee, future stock-based compensation expense that the Company has not yet recognized and the amount of tax benefits that would be recorded in additional paid-in capital when the award becomes deductible are assumed to be used to repurchase shares.
Fair Value Measures	Fair Value Measures Fair value is defined as the price that would be received from selling an asset or paid to transfer a liability (i.e., the "exit price") in an orderly transaction between market participants at the measurement date. In determining fair value, the use of various valuation methodologies, including market, income and cost approaches is permissible. The Company considers the principal or most advantageous market in which it would transact and considers assumptions that market participants would use when pricing the asset or liability. The accounting guidance for fair value measurements establishes a fair value hierarchy that requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. There are three levels of inputs that may be used to measure fair value based on the reliability of inputs. A financial instrument's categorization within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The Company's cash equivalents are classified as Level 1 while the Company's derivative instruments (foreign exchange forward contracts) are classified as Level 2. There were no Level 3 assets or liabilities held by FactSet as of August 31, 2011 or 2010.
Cash And Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents consist of demand deposits and corporate money market funds with maturities of three months or less at the date of acquisition and are reported at fair value. The Company's corporate money market funds are traded in an active market and the net asset value of each fund on the last day of the quarter is used to determine its fair value.
Accounts Receivable And Deferred Fees	Accounts Receivable and Deferred Fees Amounts that have been earned but not yet paid are reflected on the Consolidated Statements of Financial Condition as accounts receivable, net of reserves. Amounts invoiced in advance or client payments that are in excess of earned subscription revenues are reflected on the Consolidated Statements of Financial Condition as deferred fees. As of August 31, 2011, the amount of accounts receivable that was unbilled totaled $1.0 million, which was billed in fiscal 2012.
Receivable Reserve	Receivable Reserve The Company calculates its receivable reserve through analyzing aged client receivables, reviewing the recent history of client receivable write-offs and understanding general market and economic conditions. In accordance with this policy, a receivable reserve of $2.0 million and $1.9 million was recorded as of August 31, 2011 and 2010, respectively, in the Consolidated Statements of Financial Condition as a reduction of accounts receivable.
Property, Equipment And Leasehold Improvements	Property, Equipment and Leasehold Improvements Property, equipment and leasehold improvements are stated at cost, less accumulated depreciation and amortization. Computers and related equipment are depreciated on a straight-line basis over estimated useful lives of three years or less. Furniture and fixtures are depreciated on a straight-line basis over their estimated useful lives between five and seven years. Leasehold improvements are amortized on a straight-line basis over the terms of the related leases or estimated useful lives of the improvements, whichever period is shorter. Repairs and maintenance expenditures, which are not considered leasehold improvements and do not extend the useful life of the property and equipment, are expensed as incurred. The Company performs a test for impairment whenever events or changes in circumstances indicate that the carrying amount of an individual asset or asset group may not be recoverable. Should projected undiscounted future cash flows be less than the carrying amount of the asset or asset group, an impairment charge reducing the carrying amount to fair value is required. Fair value is determined based on the most appropriate valuation technique, including discounted cash flows.
Asset Retirement Obligations	Asset Retirement Obligations An asset retirement obligation is recognized in the period in which sufficient information exists to determine the fair value of the liability with a corresponding increase to the carrying amount of the related property, plant and equipment which is then depreciated over its useful life. The liability is initially measured at discounted fair value and then accretion expense is recorded in each subsequent period. The Company's asset retirement obligations are associated with its build out of office space in London where the Company made significant leasehold improvements and is obligated to remove the leasehold improvements at the end of the lease term. The Company's asset retirement obligations are not material to its consolidated financial statements.
Goodwill	Goodwill Goodwill has resulted from the acquisitions of the Insyte, LionShares, Mergerstat, CallStreet, JCF, TrueCourse, Derivative Solutions, AlphaMetrics, Global Filings, DealMaven, Thomson Fundamentals and Market Metrics businesses. Goodwill resulting from the acquisitions of LionShares, Mergerstat, TrueCourse, Derivative Solutions and Market Metrics are income tax-deductible based on the structure of the acquisition. On an ongoing basis, the Company evaluates goodwill at the reporting unit level for indications of potential impairment. Goodwill is tested for impairment based on the present value of discounted cash flows, and, if impaired, written down to fair value. FactSet has determined that there were three reporting units during fiscal years 2011, 2010 and 2009, which are consistent with the operating segments reported because there is no discrete financial information available for the subsidiaries within each operating segment. The Company's reporting units evaluated for potential impairment were U.S., Europe and Asia Pacific, which reflects the level of internal reporting the Company uses to manage its business and operations. The Company performed an annual goodwill impairment test during the fourth quarter of fiscal years 2011, 2010 and 2009 and determined that there were no reporting units that were deemed at risk and there had been no impairment.
Intangible Assets	Intangible Assets Intangible assets consist of certain acquired content databases, client relationships, software technology, non-compete agreements and trade names resulting from the acquisitions of Insyte (data central application), LionShares (global equity ownership data), Mergerstat (M&A data), CallStreet (events and transcripts), JCF (earnings and other estimates), TrueCourse (takeover defense intelligence), Derivative Solutions (fixed income), AlphaMetrics (research and performance evaluation networking tool), Global Filings (equity and fixed income prospectuses), DealMaven (investment banking workflow tool), Thomson Fundamentals (financial data) and Market Metrics (market research data on advisor-sold investments and insurance products) and depending on the nature of the intangible asset, are amortized on either a straight-line or an accelerated basis using estimated useful lives ranging between two and twenty years. These intangible assets have no assigned residual values. Intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. Determination of recoverability is based on an estimate of undiscounted future cash flows resulting from the use of the asset and its eventual disposition. Measurement of any impairment loss for intangible assets that management expects to hold and use is based on the amount the carrying value exceeds the fair value of the asset. No impairment of intangible assets has been identified during any of the periods presented.
Internal Use Software	Internal Use Software Certain costs related to computer software developed or obtained for internal use are capitalized. FactSet capitalizes only those direct costs incurred during the application development and implementation stages for developing, purchasing or otherwise acquiring software solely to meet the Company's internal needs. Capitalized costs are amortized on a straight-line basis over the estimated useful lives of the underlying software, generally three years or less. During fiscal 2011, 2010 and 2009, the Company capitalized $0.9 million, $0.8 million and $0.8 million, respectively of internal employee compensation costs associated with the application development and implementation stages for developing software for internal use only. In fiscal 2011, 2010 and 2009, FactSet recorded amortization expense related to capitalized software of $0.7 million, $0.6 million and $0.3 million, respectively.
Product Development	Product Development The Company capitalizes software development costs related to software to be sold, leased, or otherwise marketed. Capitalized software development costs include purchased materials and services, the salary and benefits for the Company's development and technical support staff and other costs associated with the enhancements of existing products and services and development of new products and services. Software development costs are expensed as incurred until technological feasibility has been established, at which time such costs are capitalized until the product is available for general release to the public. Once the point of technological feasibility is reached, which is generally the completion of a working prototype that has been certified as having no critical bugs and is a release candidate or has alternative future uses, development costs are capitalized until the product is ready for general release. Capitalized software development costs are amortized over the estimated product useful life, principally three years using the straight-line method. Research and product development costs not subject to capitalization are expensed as incurred. As of August 31, 2011 and 2010, there were no software development costs capitalized related to software to be sold, leased, or otherwise marketed.
Landlord Contributions To Leasehold Improvements	Landlord Contributions to Leasehold Improvements In conjunction with entering into leases for office space, the Company receives contributions from landlords toward leasehold improvements which are reported in the Deferred Rent and Other Non-Current Liabilities line item of the Company's Consolidated Statements of Financial Condition. These contributions are amortized as a reduction to rent expense over the non-cancelable lease terms to which they pertain. During fiscal 2011, 2010 and 2009, cash contributions from landlords were $1.4 million, $0.5 million and $2.6 million, respectively.
Derivative Instruments	Derivative Instruments FactSet conducts business outside the U.S. in several currencies including the British Pound Sterling, Euro, Japanese Yen, Indian Rupee and Philippines Peso. As such, it is exposed to movements in foreign currency exchange rates compared to the U.S. dollar. To manage the exposures related to the effects of foreign exchange rate fluctuations, the Company utilizes derivative instruments (foreign currency forward contracts). The Company's primary objective in holding derivatives is to reduce the volatility of earnings and cash flows associated with changes in foreign currency. The Company does not enter into foreign exchange forward contracts for trading or speculative purposes. These hedging programs are not designed to provide long-term foreign currency protection as the contracts have maturities of less than two years. In designing a specific hedging approach, FactSet considers several factors, including offsetting exposures, significance of exposures, forecasting risk and potential effectiveness of the hedge. These transactions are designated and accounted for as cash flow hedges in accordance with applicable accounting guidance. The changes in fair value for these foreign currency forward contracts are initially reported as a component of accumulated other comprehensive (loss) income and subsequently reclassified into operating expenses when the hedged exposure affects earnings. The gains and losses on foreign currency forward contracts mitigate the variability in operating expenses associated with currency movements. On an ongoing basis, all derivatives are assessed for effectiveness.
Accrued Liabilities	Accrued Liabilities Accrued liabilities include estimates relating to employee compensation, operating expenses and tax liabilities. Approximately 15-20% of the Company's employee incentive compensation programs are discretionary. FactSet conducts a final review of Company and departmental individual performance each fiscal year end to determine the amount of discretionary employee compensation. The Company also reviews compensation throughout the year to determine how overall performance tracks against management's expectations. Management takes these and other factors, including historical performance, into account in reviewing accrued compensation estimates quarterly and adjusting accrual rates as appropriate. The amount of the variable employee compensation recorded within accrued compensation as of August 31, 2011 and 2010, were $37.2 million and $37.5 million, respectively.
Treasury Stock	Treasury Stock The Company accounts for repurchased common stock under the cost method and includes such treasury stock as a component of its stockholders' equity. Retirement of treasury stock is recorded as a reduction of common stock and additional paid-in-capital at the time such retirement is approved by the Company's Board of Directors.
Income and Deferred Taxes	Income and Deferred Taxes Income tax expense is based on taxable income determined in accordance with current enacted laws and tax rates. Deferred income taxes are recorded for the temporary differences between the financial statement and tax bases of assets and liabilities using currently enacted tax rates. FactSet recognizes the financial effect of an income tax position only if it is more likely than not (greater than 50%) that the tax position will prevail upon tax examination, based solely on the technical merits of the tax position as of the reporting date. Otherwise, no benefit or expense can be recognized in the consolidated financial statements. The tax benefits recognized are measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. Additionally, FactSet accrues interest and related penalties, if applicable, on all tax exposures for which reserves have been established consistent with jurisdictional tax laws. Interest and penalties are classified as income tax expense in the financial statements. As of August 31, 2011, the Company had gross unrecognized tax benefits totaling $7.2 million, including $0.9 million of accrued interest, recorded as non-current taxes payable in the Statement of Financial Condition.
Comprehensive Income (Loss)	Comprehensive Income (Loss) The Company discloses comprehensive income (loss) in accordance with applicable standards for the reporting and display of comprehensive income (loss) in a set of financial statements. Comprehensive income (loss) is defined as the change in net assets of a business enterprise during a period from transactions generated from non-owner sources. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners. See Note 12 for further disclosure of comprehensive income (loss).
Foreign Currency Translation	Foreign Currency Translation Certain wholly owned subsidiaries within the Europe and Asia Pacific segments operate under a functional currency different from the U.S. dollar, such as the British Pound Sterling, Euro, Japanese Yen, Indian Rupee and Philippines Peso. The financial statements of these foreign subsidiaries are translated into U.S. dollars using period-end rates of exchange for assets and liabilities, and average rates for the period for revenues and expenses. Translation gains and losses that arise from translating assets, liabilities, revenues and expenses of foreign operations are recorded in accumulated other comprehensive income as a component of stockholders' equity. The accumulated foreign currency translation loss totaled $6.2 million and $21.1 million at August 31, 2011 and 2010, respectively.
Stock-Based Compensation	Stock-Based Compensation Accounting guidance requires the measurement and recognition of compensation expense for all share-based payment awards made to employees and directors including stock options, restricted stock and common shares acquired under employee stock purchases based on estimated fair values of the share awards that are scheduled to vest during the period. FactSet uses the straight-line attribution method for all awards with graded vesting features and service conditions only. Under this method, the amount of compensation expense that is recognized on any date is at least equal to the vested portion of the award on that date. For all stock-based awards with performance conditions, the graded vesting attribution method is used by the Company to determine the monthly stock-based compensation expense over the applicable vesting periods. As stock-based compensation expense recognized is based on awards ultimately expected to vest, it has been reduced for estimated forfeitures. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. Forfeitures were estimated based primarily on historical experience. Windfall tax benefits, defined as tax deductions that exceed recorded stock-based compensation, are classified as cash inflows from financing activities. Performance-based stock options require management to make assumptions regarding the likelihood of achieving Company performance targets on a quarterly and on-going basis. The number of performance-based options that vest will be predicated on the Company achieving certain performance levels. A change in the financial performance levels the Company achieves could result in changes to FactSet's current estimate of the vesting percentage and related stock-based compensation.
Legal Matters	Legal Matters FactSet accrues non income-tax liabilities for contingencies when management believes that a loss is probable and the amounts can be reasonably estimated, while contingent gains are recognized only when realized. From time to time, the Company is subject to legal proceedings, claims, and litigation arising in the ordinary course of business, including intellectual property litigation. Legal costs for services rendered in the course of these proceedings are charged to expense as they are incurred.
Operating Leases	Operating Leases The Company conducts all of its operations in leased facilities which have minimum lease obligations under non-cancelable operating leases. Certain of these leases contain rent escalations based on specified percentages. Most of the leases contain renewal options and require payments for taxes, insurance and maintenance. Rent expense is charged to operations as incurred except for escalating rents, which are charged to operations on a straight-line basis over the life of the lease. Lease incentives, relating to allowances provided by landlords, are amortized over the term of the lease as a reduction of rent expense. Costs associated with acquiring a subtenant, including broker commissions and tenant allowances, are amortized over the sublease term as a reduction of sublease income.