Note 9 - Dispositions (Details Textual) - Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] - Market Research Business [Member] - USD ($) $ in Millions		12 Months Ended
Jul. 01, 2016	Aug. 31, 2016
Proceeds from Divestiture of Businesses	$ 165.0
Proceeds from Divestiture of Businesses, Bonus Adjustment	$ 9.7
Gain (Loss) on Disposition of Business, Net of Tax		$ 81.7
Gain (Loss) on Disposition of Business, Tax		$ 30.8

Gain (loss) from sale or disposal of an organization or integrated set of activities, net of tax.

No definition available.

Name:	fds_GainLossOnDispositionOfBusinessNetOfTax
Namespace Prefix:	fds_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The tax effect related to gain or loss on disposition of business.

+ References

No definition available.

+ Details

Name:	fds_GainLossOnDispositionOfBusinessTax
Namespace Prefix:	fds_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This element represents the cash inflow during the period of bonus adjustment from the sale of a component of the entity.

+ References

No definition available.

+ Details

Name:	fds_ProceedsFromDivestitureOfBusinessesBonusAdjustment
Namespace Prefix:	fds_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash inflow associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3179-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

+ Details

Name:	us-gaap_ProceedsFromDivestitureOfBusinesses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_DisposalGroupClassificationAxis=us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=fds_MarketResearchBusinessMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: