REINSURANCE - Schedule of Effect of Reinsurance and Retrocessional Activity on Premiums Written and Earned and on Net Claims and Claim Expenses Incurred (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Premiums Written
Direct	$ 222,400	$ 295,213	$ 673,791	$ 935,079
Assumed	1,396,043	1,925,448	6,386,534	6,693,185
Ceded	(197,183)	(398,950)	(1,179,559)	(1,777,720)
Net premiums written	1,421,260	1,821,711	5,880,766	5,850,544
Premiums Earned
Direct	248,932	280,389	784,388	801,759
Assumed	1,862,387	2,006,596	5,609,355	5,307,078
Ceded	(355,443)	(519,964)	(1,172,055)	(1,399,008)
Net premiums earned	1,755,876	1,767,021	5,221,688	4,709,829
Claims and Claim Expenses
Gross claims and claim expenses incurred	793,869	3,096,540	2,843,229	4,913,313
Claims and claim expenses recovered	67,707	(1,128,609)	(249,242)	(1,397,410)
Net claims and claim expenses incurred	$ 861,576	$ 1,967,931	$ 2,593,987	$ 3,515,903