Lessor, Operating Lease, Payments to be Received, Two To Four Years

No definition available.

Name:	ffiv_LessorOperatingLeasePaymentsToBeReceivedTwoToFourYears
Namespace Prefix:	ffiv_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Operating Lease, Number of Square Feet

+ References

No definition available.

+ Details

Name:	ffiv_OperatingLeaseNumberofSquareFeet
Namespace Prefix:	ffiv_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_LesseeLeaseDescriptionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of lease payment to be received by lessor for operating lease in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 12
-URI https://asc.fasb.org/extlink&oid=124258985&loc=SL77919396-209981

+ Details

Name:	us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of loss from impairment of right-of-use asset from operating lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 25
-Paragraph 6
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=123399704&loc=SL77918431-209957

+ Details

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

- Definition

Amount of sublease income excluding finance and operating lease expense.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (e)
-URI https://asc.fasb.org/extlink&oid=128292326&loc=SL77918686-209980

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 55
-Paragraph 53
-URI https://asc.fasb.org/extlink&oid=123414884&loc=SL77918982-209971

+ Details

Name:	us-gaap_SubleaseIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Leases - Narrative (Details) $ in Millions	3 Months Ended		12 Months Ended
Leases - Narrative (Details) $ in Millions	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Sep. 30, 2022 USD ($) ft²	Sep. 30, 2020 USD ($)
Lessee, Lease, Description [Line Items]
Sublease Income			$ 21.6
Lessor, Operating Lease, Payments to be Received, Next Twelve Months			7.5
Lessor, Operating Lease, Payments to be Received, Two To Four Years			$ 14.1
Operating Lease, Impairment Loss	$ 23.5	$ 6.7		$ 9.7
Office Building [Member]
Lessee, Lease, Description [Line Items]
Operating Lease, Number of Square Feet \| ft²			515,000