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v3.26.1

Borrowings under Financing Agreement (Details) - Line of Credit - USD ($) $ in Millions |  |  | 3 Months Ended | 6 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | --- | ---
Jun. 22, 2026 | Jun. 28, 2023 | Jun. 30, 2026 | Jun. 30, 2025 | Jun. 30, 2026 | Jun. 30, 2025 | Dec. 31, 2025 | Feb. 03, 2025 | Jan. 08, 2024
Customer Investment Agreement |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Maximum amount of borrowings |  | $ 150.0 |  |  |  |  |  |  |
Term of borrowings |  | 18 months |  |  |  |  |  |  |
Borrowings outstanding |  |  | $ 206.4 |  | $ 206.4 |  | $ 158.1 |  |
Interest expense |  |  | $ 7.0 | $ 4.0 | $ 13.2 | $ 7.3 |  |  |
Customer Investment Agreement | GC Customer Value Arranger, LLC |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Internal rate of return on growth pend |  | 16.00% |  |  |  |  |  |  |
Customer Investment Agreement | Minimum | GC Customer Value Arranger, LLC |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Investment amount, percent of growth spend up to 80% |  | 50.00% |  |  |  |  |  |  |
Customer Investment Agreement | Maximum | GC Customer Value Arranger, LLC |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Investment amount, percent of growth spend up to 80% |  | 80.00% |  |  |  |  |  |  |
Amended and Restated Customer Investment Agreement |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Additional financing |  |  |  |  |  |  |  | $ 200.0 | $ 140.0
New Business Financing Agreement |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Maximum amount of borrowings | $ 250.0 |  |  |  |  |  |  |  |
Line of credit facility, funding percentage | 80.00% |  |  |  |  |  |  |  |
Line of credit facility maximum borrowing capacity per reference cohort | $ 20.0 |  |  |  |  |  |  |  |
New Business Financing Agreement | Reference Premium |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Debt instrument, basis spread on variable rate (as a percent) | 0.00% |  |  |  |  |  |  |  |
New Business Financing Agreement | Three-Year U.S. Treasury Bill Rate |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Debt instrument, basis spread on variable rate (as a percent) | 5.80% |  |  |  |  |  |  |  |
New Business Financing Agreement | Debt Instrument, Funding Period Two |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Maximum amount of borrowings | $ 250.0 |  |  |  |  |  |  |  |
New Business Financing Agreement | Debt Instrument, Funding Period One |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Maximum amount of borrowings | $ 150.0 |  |  |  |  |  |  |  |

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Name: | lmnd_DebtInstrumentFundingPeriodAxis=lmnd_DebtInstrumentFundingPeriodOneMember
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Data Type: | na
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