GEOGRAPHICAL BREAKDOWN OF GROSS PREMIUMS WRITTEN (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Effects of Reinsurance [Line Items]
Total	$ 331.7	$ 224.2	$ 970.6	$ 503.9
Texas
Effects of Reinsurance [Line Items]
Total	63.6	36.8	186.9	80.1
Georgia
Effects of Reinsurance [Line Items]
Total	38.6	26.3	119.1	56.0
Florida
Effects of Reinsurance [Line Items]
Total	27.6	2.9	71.6	6.7
Colorado
Effects of Reinsurance [Line Items]
Total	19.3	15.3	54.8	37.8
Pennsylvania
Effects of Reinsurance [Line Items]
Total	19.1	12.1	54.4	29.0
South Carolina
Effects of Reinsurance [Line Items]
Total	14.5	11.8	46.1	28.6
Arizona
Effects of Reinsurance [Line Items]
Total	12.1	11.0	38.7	21.7
California
Effects of Reinsurance [Line Items]
Total	15.7	2.1	29.8	5.4
Ohio
Effects of Reinsurance [Line Items]
Total	9.0	8.4	29.1	16.9
Maryland
Effects of Reinsurance [Line Items]
Total	8.4	6.7	26.3	13.0
All others states
Effects of Reinsurance [Line Items]
Total	$ 103.8	$ 90.8	$ 313.8	$ 208.7
Geographic Concentration Risk | Gross Written Premiums | United States
Effects of Reinsurance [Line Items]
Concentration percentage (in percent)	100.00%	100.00%	100.00%	100.00%
Geographic Concentration Risk | Gross Written Premiums | Texas
Effects of Reinsurance [Line Items]
Concentration percentage (in percent)	19.20%	16.40%	19.30%	15.90%
Geographic Concentration Risk | Gross Written Premiums | Georgia
Effects of Reinsurance [Line Items]
Concentration percentage (in percent)	11.60%	11.70%	12.30%	11.10%
Geographic Concentration Risk | Gross Written Premiums | Florida
Effects of Reinsurance [Line Items]
Concentration percentage (in percent)	8.30%	1.30%	7.40%	1.30%
Geographic Concentration Risk | Gross Written Premiums | Colorado
Effects of Reinsurance [Line Items]
Concentration percentage (in percent)	5.80%	6.80%	5.60%	7.50%
Geographic Concentration Risk | Gross Written Premiums | Pennsylvania
Effects of Reinsurance [Line Items]
Concentration percentage (in percent)	5.80%	5.40%	5.60%	5.80%
Geographic Concentration Risk | Gross Written Premiums | South Carolina
Effects of Reinsurance [Line Items]
Concentration percentage (in percent)	4.40%	5.30%	4.70%	5.70%
Geographic Concentration Risk | Gross Written Premiums | Arizona
Effects of Reinsurance [Line Items]
Concentration percentage (in percent)	3.60%	4.90%	4.00%	4.30%
Geographic Concentration Risk | Gross Written Premiums | California
Effects of Reinsurance [Line Items]
Concentration percentage (in percent)	4.70%	0.90%	3.10%	1.10%
Geographic Concentration Risk | Gross Written Premiums | Ohio
Effects of Reinsurance [Line Items]
Concentration percentage (in percent)	2.70%	3.70%	3.00%	3.40%
Geographic Concentration Risk | Gross Written Premiums | Maryland
Effects of Reinsurance [Line Items]
Concentration percentage (in percent)	2.50%	3.00%	2.70%	2.60%
Geographic Concentration Risk | Gross Written Premiums | All others states
Effects of Reinsurance [Line Items]
Concentration percentage (in percent)	31.40%	40.60%	32.30%	41.30%