Related Party Transactions (Details)		12 Months Ended
	Feb. 18, 2020 shares	Dec. 31, 2023 USD ($) director	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($) $ / shares shares
Related Party Transaction [Line Items]
Other assets		$ 63,800,000	$ 75,200,000
Other liabilities and accrued expenses		99,500,000	84,500,000
Immediate Family Member of Management or Principal Owner
Related Party Transaction [Line Items]
Travel and entertainment expense		$ 100,000	200,000	$ 100,000
Affiliated entity | The Lemonade Foundation
Related Party Transaction [Line Items]
Number of shared directors | director		2
Contribution to the Lemonade Foundation (in shares) | shares	500,000			500,000
Contribution of common stock to related party, fair value (usd per share) | $ / shares				$ 24.36
Other assets		$ 0
Other liabilities and accrued expenses			0
Related Party
Related Party Transaction [Line Items]
Other assets		$ 0
Other liabilities and accrued expenses			$ 0