INVESTMENTS - Schedule of Net Realized and Unrealized Gains (Losses) on Investments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Gain (Loss) on Securities [Line Items]
Net realized and unrealized gains (losses) on investments	$ (222,781)	$ (654,107)	$ 56,670	$ (1,327,124)
Fixed maturity investments trading
Gain (Loss) on Securities [Line Items]
Net realized gains (losses) on fixed maturity investments trading	(74,212)	(287,154)	(178,977)	(408,306)
Net unrealized gains (losses) on fixed maturity investments trading	(139,793)	(149,820)	172,233	(613,997)
Net realized and unrealized gains (losses) on fixed maturity investments trading	(214,005)	(436,974)	(6,744)	(1,022,303)
Derivatives
Gain (Loss) on Securities [Line Items]
Net realized and unrealized gains (losses) on investments-related derivatives	(65,051)	(66,078)	(52,889)	(106,366)
Equity investments
Gain (Loss) on Securities [Line Items]
Net realized gains (losses) on equity investments	(18,755)	35,592	(27,493)	35,572
Net unrealized gains (losses) on equity investments	20,627	(127,104)	59,778	(175,773)
Net realized and unrealized gains (losses) on equity investments	1,872	(91,512)	32,285	(140,201)
Catastrophe bonds
Gain (Loss) on Securities [Line Items]
Net realized and unrealized gains (losses) on other investments	38,186	(24,660)	62,312	(32,921)
Other
Gain (Loss) on Securities [Line Items]
Net realized and unrealized gains (losses) on other investments	$ 16,217	$ (34,883)	$ 21,706	$ (25,333)