DERIVATIVE INSTRUMENTS - Gains (Losses) on Derivatives Recognized in Net Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Unrealized and Realized Gains (Losses) Recognized in Earnings for Derivatives Not Designated As Hedges [Line Items]
Unrealized and realized gains (losses) recognized in earnings for derivatives not designated as hedges	$ (3,540)	$ (25,957)	$ 6,763	$ (51,137)
Relating to investment portfolio: | Foreign exchange forward contracts | Net investment gains (losses)
Unrealized and Realized Gains (Losses) Recognized in Earnings for Derivatives Not Designated As Hedges [Line Items]
Unrealized and realized gains (losses) recognized in earnings for derivatives not designated as hedges	(527)	4,822	(1,474)	7,063
Relating to underwriting portfolio: | Foreign exchange forward contracts | Foreign exchange (losses) gains
Unrealized and Realized Gains (Losses) Recognized in Earnings for Derivatives Not Designated As Hedges [Line Items]
Unrealized and realized gains (losses) recognized in earnings for derivatives not designated as hedges	(3,013)	(31,146)	8,237	(59,122)
Relating to underwriting portfolio: | Other Contract | Other insurance related income (losses)
Unrealized and Realized Gains (Losses) Recognized in Earnings for Derivatives Not Designated As Hedges [Line Items]
Unrealized and realized gains (losses) recognized in earnings for derivatives not designated as hedges	$ 0	$ 367	$ 0	$ 922