Reinsurance - Additional Information (Details) - USD ($)	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2024	Jun. 30, 2024	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Reinsurance Retention Policy
Document Period End Date			Dec. 31, 2025
Ceded premiums earned			$ 341,408,000	$ 364,618,000	$ 342,623,000
Ceded losses incurred decreased			201,982,000	201,982,000
Hurricane Milton
Reinsurance Retention Policy
Ceded losses incurred decreased			75,500,000	$ 125,000,000
Reinsurance Contract [Axis]: XOL Commutation
Reinsurance Retention Policy
Ceded premiums earned	$ 6,300,000	$ 15,700,000
All Other Perilds Catastrophe Excess of Loss | American Coastal Insurance Company
Reinsurance Retention Policy
Reinsurance, excess retention, amount reinsured, per policy			$ 176,400,000
Program provides sufficient coverage return period			1-in-450-year
Percentage of singe occurrence exceeding protection purchased			0.20%
Reinsurance, excess retention level per event			$ 88,200,000
Catastrophe Aggregate Excess of Loss | American Coastal Insurance Company
Reinsurance Retention Policy
Reinsurance, excess retention, amount reinsured, per policy			40,000,000
Event occurrence limit			20,000,000
Reinsurance, aggregate retention			40,000,000
Catastrophe Excess of Loss
Reinsurance Retention Policy
Retension loss events			100,000,000
Third Event Retention Level			3,750,000
First Event Retention Level			29,750,000
Second event retention level			18,500,000
Catastrophe Excess of Loss | American Coastal Insurance Company
Reinsurance Retention Policy
Reinsurance, excess retention, amount reinsured, per policy			1,676,000,000
Event Retention Level			$ 14,000,000
Program provides sufficient coverage return period			1-in-203-year
Program provides sufficient coverage period			1-in-100-year
Percentage of singe occurrence exceeding protection purchased			0.50%
Insured long term debt project demand decrease			$ 69,000,000,000
Reinsurance, excess retention, amount reinsured, per event			1,330,000,000
Catastrophe Excess of Loss | UPC Re
Reinsurance Retention Policy
First Event Retention Level			15,750,000
Subsequent Event Retention Level			$ 4,500,000
Quota Share Agreement | Shoreline Re
Reinsurance Retention Policy
Cession Rate			45.00%
Quota Share Agreement | Shoreline Re | Reinsurance Contract [Axis]: 06/01/2024 - 05/31/2026
Reinsurance Retention Policy
Cession Rate			30.00%
Quota Share Agreement | Shoreline Re | Reinsurance Contract [Axis]: 06/01/2025 - 05/31/2026
Reinsurance Retention Policy
Cession Rate			45.00%
Maximum [Member] | Catastrophe Excess of Loss | American Coastal Insurance Company
Reinsurance Retention Policy
Program provides sufficient coverage probability rate			0.10%