RESERVE FOR LOSSES AND LOSS EXPENSES - Prior Year Development (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Liability for Claims and Claims Adjustment Expense [Line Items]
Prior years - net favorable (adverse) effect	$ 2,762	$ 4,735	$ 13,118	$ 17,632
Insurance
Liability for Claims and Claims Adjustment Expense [Line Items]
Prior years - net favorable (adverse) effect	1,609	2,558	5,433	12,396
Reinsurance
Liability for Claims and Claims Adjustment Expense [Line Items]
Prior years - net favorable (adverse) effect	$ 1,153	$ 2,177	$ 7,685	$ 5,236