SEGMENT REPORTING - Gross Premiums Written by Line of Business (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) segment	Sep. 30, 2023 USD ($)
Segment Reporting Information
Number of operating segments | segment			1
Gross premiums written	$ 168,346	$ 183,074	$ 554,579	$ 524,472
Gross premiums written (in percent)	100.00%	100.00%	100.00%	100.00%
Total Property
Segment Reporting Information
Gross premiums written	$ 13,625	$ 32,940	$ 61,578	$ 94,660
Gross premiums written (in percent)	8.10%	18.00%	11.00%	18.00%
Commercial
Segment Reporting Information
Gross premiums written	$ 14,794	$ 16,105	$ 45,030	$ 45,236
Gross premiums written (in percent)	8.80%	8.80%	8.00%	8.60%
Motor
Segment Reporting Information
Gross premiums written	$ 189	$ 122	$ 344	$ 706
Gross premiums written (in percent)	0.10%	0.10%	0.10%	0.10%
Personal
Segment Reporting Information
Gross premiums written	$ (1,358)	$ 16,713	$ 16,204	$ 48,718
Gross premiums written (in percent)	(0.80%)	9.10%	2.90%	9.30%
Total Casualty
Segment Reporting Information
Gross premiums written	$ 92,124	$ 108,964	$ 279,118	$ 284,560
Gross premiums written (in percent)	54.70%	59.50%	50.40%	54.20%
General Liability
Segment Reporting Information
Gross premiums written	$ 28,084	$ 31,325	$ 83,482	$ 79,401
Gross premiums written (in percent)	16.70%	17.10%	15.10%	15.10%
Motor Liability
Segment Reporting Information
Gross premiums written	$ 2,900	$ 2,917	$ 17,556	$ 11,223
Gross premiums written (in percent)	1.70%	1.60%	3.20%	2.10%
Professional Liability
Segment Reporting Information
Gross premiums written	$ 33	$ 1,625	$ 152	$ 4,850
Gross premiums written (in percent)	0.00%	0.90%	0.00%	0.90%
Workers' Compensation
Segment Reporting Information
Gross premiums written	$ 939	$ 4,484	$ 4,319	$ 11,542
Gross premiums written (in percent)	0.60%	2.40%	0.80%	2.20%
Multi-line
Segment Reporting Information
Gross premiums written	$ 60,168	$ 68,613	$ 173,609	$ 177,544
Gross premiums written (in percent)	35.70%	37.50%	31.30%	33.90%
Total Other
Segment Reporting Information
Gross premiums written	$ 62,597	$ 41,170	$ 213,883	$ 145,252
Gross premiums written (in percent)	37.20%	22.50%	38.60%	27.80%
Accident & Health
Segment Reporting Information
Gross premiums written	$ 2,329	$ 1,695	$ 6,207	$ 6,184
Gross premiums written (in percent)	1.40%	0.90%	1.10%	1.20%
Financial
Segment Reporting Information
Gross premiums written	$ 11,868	$ 17,059	$ 50,012	$ 48,406
Gross premiums written (in percent)	7.00%	9.30%	9.00%	9.20%
Marine
Segment Reporting Information
Gross premiums written	$ 11,200	$ 3,973	$ 41,642	$ 23,967
Gross premiums written (in percent)	6.70%	2.20%	7.50%	4.60%
Other Specialty
Segment Reporting Information
Gross premiums written	$ 37,200	$ 18,443	$ 116,022	$ 66,695
Gross premiums written (in percent)	22.10%	10.10%	21.00%	12.80%