Number of Floors Subleased

No definition available.

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Balance Type:	na
Period Type:	instant

- Definition

Number Of Leases

+ References

No definition available.

+ Details

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Namespace Prefix:	lmnd_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- 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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479773/842-30-50-3

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 25
-Paragraph 6
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479365/842-20-25-6

+ Details

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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/exampleRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 53
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479589/842-20-55-53

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147478964/842-20-50-4

+ Details

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

- Details

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Data Type:	na
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- Details

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Leases - Additional Information (Details) $ in Millions	3 Months Ended	12 Months Ended
Leases - Additional Information (Details) $ in Millions	Dec. 31, 2023 USD ($) leaseAgreement	Dec. 31, 2023 USD ($) leaseAgreement	Sep. 30, 2023 floor
Lessor, Lease, Description [Line Items]
Number of leases \| leaseAgreement	2	2
New York
Lessor, Lease, Description [Line Items]
Number of floors leased \| floor			2
Sublease income	$ 0.4
Impairment loss on subleased right-of-use asset		$ 0.0
San Francisco
Lessor, Lease, Description [Line Items]
Sublease income	$ 0.2
Impairment loss on subleased right-of-use asset		$ 3.7