RESERVE FOR CLAIMS AND CLAIM EXPENSES - Schedule of Liability for Unpaid Claims and Claim Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Reserve for claims and claim expenses, net of reinsurance recoverable, as of beginning of period			$ 11,181,648	$ 9,025,961
Net incurred related to:
Current year	$ 1,019,523	$ 1,999,837	2,888,784	3,608,599
Prior years	(157,947)	(31,906)	(294,797)	(92,696)
Total net incurred	861,576	1,967,931	2,593,987	3,515,903
Net paid related to:
Current year			181,155	101,258
Prior years			1,880,700	1,454,977
Total net paid			2,061,855	1,556,235
Foreign exchange			(11,874)	(291,918)
Reserve for claims and claim expenses, net of reinsurance recoverable, as of end of period	11,701,906	10,693,711	11,701,906	10,693,711
Reinsurance recoverable as of end of period	4,253,259	4,969,244	4,253,259	4,969,244	$ 4,710,925
Reserve for claims and claim expenses as of end of period	$ 15,955,165	$ 15,662,955	$ 15,955,165	$ 15,662,955