Significant Accounting Policies (Policies)	6 Months Ended
Feb. 28, 2018
Accounting Policies [Abstract]
New Accounting Pronouncements, Policy [Policy Text Block]	New Accounting Standards or Updates Recently Adopted Balance Sheet Classification of Deferred Taxes During the first quarter of fiscal 2018, FactSet adopted the accounting standard update issued by the FASB in November 2015 to simplify the presentation of deferred taxes on the balance sheet. This accounting standard update required an entity to present all deferred tax assets and deferred tax liabilities as non-current on the balance sheet. Under the previous guidance, entities were required to separately present deferred taxes as current or non-current. Netting deferred tax assets and deferred tax liabilities by tax jurisdiction is still required under the new guidance. This accounting standard update is a change to the balance sheet presentation only. The changes have been applied prospectively as permitted by the standard and prior periods have not been restated. Share-Based Payments During the first quarter of fiscal 2018, FactSet adopted the accounting standard update issued by the FASB in March 2016, which simplifies several aspects of the accounting for employee share-based payment transactions, including the accounting for income taxes, forfeitures and statutory tax withholding requirements, as well as classification in the statement of cash flows. This accounting standard update increases the volatility within the Company’s provision for income taxes as all excess tax benefits or deficiencies related to share-based payments that were previously reported within equity are now recognized in the consolidated statement of income. The adoption of this standard resulted in the recognition of $6.1 million of excess tax benefits to FactSet’s provision for income taxes during the first six months of fiscal 2018. In addition, this standard changed the classification of excess tax benefits presented in the Company's consolidated statements of cash flows from a financing activity to an operating activity, which was applied on a prospective basis as permitted by the standard. Prior periods were not restated. Share-based payment expense continues to reflect estimated forfeitures of share-based payment awards. The remaining provisions of this standard did not have a material impact on the Company’s consolidated financial statements. Recent Accounting Standards or Updates Not Yet Effective Revenue Recognition In May 2014 and July 2015, the FASB issued accounting standard updates, which clarified principles for recognizing revenue arising from contracts with clients and superseded most current revenue recognition guidance, including industry-specific guidance. The core principle of the revenue model is that an entity recognizes revenue to depict the transfer of promised goods or services to clients in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. These accounting standard updates will be effective for FactSet beginning in the first quarter of fiscal 2019, with early adoption in fiscal 2018 permitted, and will allow for either full retrospective or modified retrospective adoption. The Company plans to adopt the standard on September 1, 2018, and is currently evaluating the impact of these accounting standard updates on its consolidated financial statements and the method of adoption. Recognition and Measurement of Financial Assets and Financial Liabilities In January 2016, the FASB issued an accounting standard update to amend its current guidance on the classification and measurement of certain financial instruments. The accounting standard update significantly revises an entity’s accounting related to the presentation of certain fair value changes for financial liabilities measured at fair value. This guidance also amends certain disclosure requirements associated with the fair value of financial instruments. This guidance will be effective for FactSet beginning in the first quarter of fiscal 2019. The Company is currently evaluating the impact of this accounting standard update on its consolidated financial statements. Leases In February 2016, the FASB issued an accounting standard update related to accounting for leases. The guidance introduces a lessee model that requires most leases to be reported on the balance sheet. The accounting standard update aligns many of the underlying principles of the new lessor model with those in the FASB’s new revenue recognition standard. The guidance also eliminates the requirement in current U.S. GAAP for an entity to use bright-line tests in determining lease classification. This accounting standard update will be effective for FactSet beginning in the first quarter of fiscal 2020, with early adoption in fiscal 2019 permitted. The Company is currently evaluating the impact of this accounting standard update on its consolidated financial statements. Cash Flow Simplification In August 2016, the FASB issued an accounting standard update, which simplifies how certain transactions are classified in the statement of cash flows. This includes revised guidance on the cash flow classification of debt prepayments and debt extinguishment costs, contingent consideration payments made after a business combination and distributions received from equity method investments. The guidance is intended to reduce diversity in practice across all industries. This accounting standard update will be effective for FactSet beginning in the first quarter of fiscal 2019. The Company is currently evaluating the impact of this accounting standard update on its consolidated financial statements. Income Taxes on Intra-Entity Transfer s of Asset s In October 2016, the FASB issued an accounting standard update, which removes the prohibition against the immediate recognition of the current and deferred income tax effects of intra-entity transfers of assets other than inventory. The guidance is intended to reduce diversity in practice related to the tax consequences of certain types of intra-entity asset transfers, particularly those involving intellectual property. This accounting standard update will be effective for FactSet beginning in the first quarter of fiscal 2019. The Company is currently evaluating the impact of this accounting standard update on its consolidated financial statements. Goodwill Impairment Test In January 2017, the FASB issued an accounting standard update, which removes the requirement for companies to compare the implied fair value of goodwill with its carrying amount as part of step 2 of the goodwill impairment test. A goodwill impairment will now be the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. This accounting standard update will be effective for FactSet beginning in the first quarter of fiscal 2021, with early adoption permitted for any impairment tests performed after January 1, 2017. The Company is currently evaluating the impact of this accounting standard update on its consolidated financial statements. Hedge Accounting Simplification In August 2017, the FASB issued an accounting standard update to reduce the complexity and simplify the application of hedging accounting. The guidance refines and expands hedge accounting for both financial and nonfinancial risk components, eliminates the need to separately measure and report hedge ineffectiveness, and aligns the recognition and presentation of the effects of the hedging instrument and the hedged item in the financial statements. This guidance will be effective for FactSet beginning in the first quarter of fiscal 2020, with early adoption permitted. The Company is currently evaluating the impact of this accounting standard update on its consolidated financial statements. Share-Based Payments In May 2017, the FASB issued an accounting standard update, which amends the scope of modification accounting for share-based payment arrangements. The guidance focuses on changes to the terms or conditions of share-based payment awards that would require the application of modification accounting and specifies that an entity would not apply modification accounting if the fair value, vesting conditions and classification of the awards are the same immediately before and after the modification. This accounting standard update will be effective for FactSet beginning in the first quarter of fiscal 2019, with early adoption permitted. The Company is currently evaluating the impact of this accounting standard update on its consolidated financial statements. Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income In February 2018, the FASB issued an accounting standard update, which allows companies to reclassify certain stranded income tax effects resulting from the enactment of the Tax Cuts and Jobs Act (the "TCJA") from accumulated other comprehensive income to retained earnings. This accounting standard update will be effective for FactSet beginning in the first quarter of fiscal 2019, with early adoption permitted. The Company is currently evaluating the impact of this accounting standard update on its consolidated financial statements. No other new accounting pronouncements issued or effective as of February 28, 2018 have had or are expected to have an impact on the Company’s consolidated financial statements.

New Accounting Standards or Updates Recently Adopted

Balance Sheet Classification of Deferred Taxes

During the

first

quarter of fiscal

2018,

FactSet adopted the accounting standard update issued by the FASB in

November 2015

to simplify the presentation of deferred taxes on the balance sheet. This accounting standard update required an entity to present all deferred tax assets and deferred tax liabilities as non-current on the balance sheet. Under the previous guidance, entities were required to separately present deferred taxes as current or non-current. Netting deferred tax assets and deferred tax liabilities by tax jurisdiction is still required under the new guidance. This accounting standard update is a change to the balance sheet presentation only. The changes have been applied prospectively as permitted by the standard and prior periods have

not

been restated.

Share-Based Payments

During the

first

quarter of fiscal

2018,

FactSet adopted the accounting standard update issued by the FASB in

March 2016,

which simplifies several aspects of the accounting for employee share-based payment transactions, including the accounting for income taxes, forfeitures and statutory tax withholding requirements, as well as classification in the statement of cash flows. This accounting standard update increases the volatility within the Company’s provision for income taxes as all excess tax benefits or deficiencies related to share-based payments that were previously reported within equity are now recognized in the consolidated statement of income. The adoption of this standard resulted in the recognition of

$6.1

million of excess tax benefits to FactSet’s provision for income taxes during the

first

six

months of fiscal

2018.

In addition, this standard changed the classification of excess tax benefits presented in the Company's consolidated statements of cash flows from a financing activity to an operating activity, which was applied on a prospective basis as permitted by the standard. Prior periods were

not

restated. Share-based payment expense continues to reflect estimated forfeitures of share-based payment awards. The remaining provisions of this standard did

not

have a material impact on the Company’s consolidated financial statements.

Recent Accounting Standards or Updates

Not

Yet Effective

Revenue Recognition

May 2014

and

July 2015,

the FASB issued accounting standard updates, which clarified principles for recognizing revenue arising from contracts with clients and superseded most current revenue recognition guidance, including industry-specific guidance. The core principle of the revenue model is that an entity recognizes revenue to depict the transfer of promised goods or services to clients in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. These accounting standard updates will be effective for FactSet beginning in the

first

quarter of fiscal

2019,

with early adoption in fiscal

2018

permitted, and will allow for either full retrospective or modified retrospective adoption. The Company plans to adopt the standard on

September 1, 2018,

and is currently evaluating the impact of these accounting standard updates on its consolidated financial statements and the method of adoption.

Recognition and Measurement of Financial Assets and Financial Liabilities

January 2016,

the FASB issued an accounting standard update to amend its current guidance on the classification and measurement of certain financial instruments. The accounting standard update significantly revises an entity’s accounting related to the presentation of certain fair value changes for financial liabilities measured at fair value. This guidance also amends certain disclosure requirements associated with the fair value of financial instruments. This guidance will be effective for FactSet beginning in the

first

quarter of fiscal

2019.

The Company is currently evaluating the impact of this accounting standard update on its consolidated financial statements.

Leases

February 2016,

the FASB issued an accounting standard update related to accounting for leases. The guidance introduces a lessee model that requires most leases to be reported on the balance sheet. The accounting standard update aligns many of the underlying principles of the new lessor model with those in the FASB’s new revenue recognition standard. The guidance also eliminates the requirement in current U.S. GAAP for an entity to use bright-line tests in determining lease classification. This accounting standard update will be effective for FactSet beginning in the

first

quarter of fiscal

2020,

with early adoption in fiscal

2019

permitted. The Company is currently evaluating the impact of this accounting standard update on its consolidated financial statements.

Cash Flow Simplification

August 2016,

the FASB issued an accounting standard update, which simplifies how certain transactions are classified in the statement of cash flows. This includes revised guidance on the cash flow classification of debt prepayments and debt extinguishment costs, contingent consideration payments made after a business combination and distributions received from equity method investments. The guidance is intended to reduce diversity in practice across all industries. This accounting standard update will be effective for FactSet beginning in the

first

quarter of fiscal

2019.

The Company is currently evaluating the impact of this accounting standard update on its consolidated financial statements.

Income Taxes on

Intra-Entity Transfer

s of Asset

October 2016,

the FASB issued an accounting standard update, which removes the prohibition against the immediate recognition of the current and deferred income tax effects of intra-entity transfers of assets other than inventory. The guidance is intended to reduce diversity in practice related to the tax consequences of certain types of intra-entity asset transfers, particularly those involving intellectual property. This accounting standard update will be effective for FactSet beginning in the

first

quarter of fiscal

2019.

The Company is currently evaluating the impact of this accounting standard update on its consolidated financial statements.

Goodwill Impairment Test

January 2017,

the FASB issued an accounting standard update, which removes the requirement for companies to compare the implied fair value of goodwill with its carrying amount as part of step

of the goodwill impairment test. A goodwill impairment will now be the amount by which a reporting unit’s carrying value exceeds its fair value,

not

to exceed the carrying amount of goodwill. This accounting standard update will be effective for FactSet beginning in the

first

quarter of fiscal

2021,

with early adoption permitted for any impairment tests performed after

January 1, 2017.

The Company is currently evaluating the impact of this accounting standard update on its consolidated financial statements.

Hedge Accounting Simplification

August 2017,

the FASB issued an accounting standard update to reduce the complexity and simplify the application of hedging accounting. The guidance refines and expands hedge accounting for both financial and nonfinancial risk components, eliminates the need to separately measure and report hedge ineffectiveness, and aligns the recognition and presentation of the effects of the hedging instrument and the hedged item in the financial statements. This guidance will be effective for FactSet beginning in the

first

quarter of fiscal

2020,

with early adoption permitted. The Company is currently evaluating the impact of this accounting standard update on its consolidated financial statements.

Share-Based Payments

May 2017,

the FASB issued an accounting standard update, which amends the scope of modification accounting for share-based payment arrangements. The guidance focuses on changes to the terms or conditions of share-based payment awards that would require the application of modification accounting and specifies that an entity would

not

apply modification accounting if the fair value, vesting conditions and classification of the awards are the same immediately before and after the modification. This accounting standard update will be effective for FactSet beginning in the

first

quarter of fiscal

2019,

with early adoption permitted. The Company is currently evaluating the impact of this accounting standard update on its consolidated financial statements.

Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income

February 2018,

the FASB issued an accounting standard update, which allows companies to reclassify certain stranded income tax effects resulting from the enactment of the Tax Cuts and Jobs Act (the "TCJA") from accumulated other comprehensive income to retained earnings. This accounting standard update will be effective for FactSet beginning in the

first

quarter of fiscal

2019,

with early adoption permitted. The Company is currently evaluating the impact of this accounting standard update on its consolidated financial statements.

other new accounting pronouncements issued or effective as of

February 28, 2018

have had or are expected to have an impact on the Company’s consolidated financial statements.