Reinsurance, Per Risk Limit, Amount

No definition available.

Name:	lmnd_ReinsurancePerRiskLimitAmount
Namespace Prefix:	lmnd_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Reinsurance Program, Minimum Losses Threshold

+ References

No definition available.

+ Details

Name:	lmnd_ReinsuranceProgramMinimumLossesThreshold
Namespace Prefix:	lmnd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Ratio of insurance contracts that are subject to reinsurance participation to all contracts in force.

+ References

No definition available.

+ Details

Name:	us-gaap_ContractsInForceSubjectToParticipationThroughReinsurancePercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
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_EffectsOfReinsuranceLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount per event of risk undertaken originally by insurer that is not ceded to reinsurer.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479838/944-20-50-3

+ Details

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

- Definition

Amount per event of risk ceded to reinsurer in excess of risk undertaken originally by insurer that is not ceded to reinsurer.

+ References

+ Details

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

- Definition

Amount per policy of risk ceded to reinsurer in excess of risk undertaken originally by insurer that is not ceded to reinsurer.

+ References

+ Details

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

- Definition

Percentage of risk ceded to reinsurer in excess of risk undertaken originally by insurer that is not ceded to reinsurer.

+ References

+ Details

Name:	us-gaap_ReinsuranceRetentionPolicyExcessRetentionPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_ReinsuranceContractAxis=Automatic Facultative Property Per Risk Excess of Loss
Namespace Prefix:
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Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=lmnd_LemonadeInsuranceCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ReinsuranceContractAxis=Automatic Facultative Property Per Risk Excess of Loss Reinsurance
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ReinsuranceContractAxis=Excess of Loss Reinsurance Contract
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ReinsuranceContractAxis=Property Per Risk Excess of Loss Reinsurance
Namespace Prefix:
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- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
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- Details

Name:	us-gaap_ReinsuranceContractAxis=Proportional Reinsurance Contracts
Namespace Prefix:
Data Type:	na
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- Details

Name:	us-gaap_ReinsuranceContractAxis=Quota Share Reinsurance
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Reinsurance - Additional Information (Details) - USD ($)				6 Months Ended	18 Months Ended
	Jul. 01, 2023	Jul. 01, 2022	Jul. 01, 2021	Jun. 30, 2022	Jun. 30, 2023
Effects of Reinsurance [Line Items]
Reinsurance program, minimum losses threshold				$ 80,000,000
Reinsurance, Excess Retention, Amount Reinsured, Per Event	$ 5,000,000
Reinsurance, Per Risk Limit, Amount	750,000
Reinsurance Contract [Axis]: Automatic Facultative Property Per Risk Excess of Loss \| Lemonade Insurance Company
Effects of Reinsurance [Line Items]
Reinsurance, Excess Retention, Amount Reinsured, Per Policy	3,000,000
Reinsurance Contract [Axis]: Automatic Facultative Property Per Risk Excess of Loss Reinsurance \| Lemonade Insurance Company
Effects of Reinsurance [Line Items]
Reinsurance, Excess Retention, Amount Reinsured, Per Policy	$ 10,000,000
Reinsurance, Excess Retention, Percentage	100.00%
Reinsurance Contract [Axis]: Excess of Loss Reinsurance Contract
Effects of Reinsurance [Line Items]
Reinsurance, Excess Retention, Amount Reinsured, Per Event	$ 80,000,000
Reinsurance, Amount Retained, Per Event	50,000,000
Reinsurance Contract [Axis]: Property Per Risk Excess of Loss Reinsurance
Effects of Reinsurance [Line Items]
Reinsurance, Excess Retention, Amount Reinsured, Per Policy	$ 2,250,000
Reinsurance, Excess Retention, Percentage	100.00%
Reinsurance Contract [Axis]: Property Per Risk Excess of Loss Reinsurance \| Maximum
Effects of Reinsurance [Line Items]
Reinsurance, Excess Retention, Amount Reinsured, Per Policy	$ 750,000
Reinsurance Contract [Axis]: Proportional Reinsurance Contracts
Effects of Reinsurance [Line Items]
Percent of contracts subject to participation through reinsurance	55.00%	55.00%	70.00%	75.00%
Reinsurance Contract [Axis]: Quota Share Reinsurance
Effects of Reinsurance [Line Items]
Percent of contracts subject to participation through reinsurance					30.00%