RESERVE FOR CLAIMS AND CLAIM EXPENSES - Schedule of Liability for Unpaid Claims and Claims Adjustment Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 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	905,952	859,566
Prior years	(104,752)	(17,833)
Total net incurred	801,200	841,733
Net paid related to:
Current year	26,969	17,790
Prior years	690,868	608,805
Total net paid	717,837	626,595
Foreign exchange	25,144	(50,285)
Reserve for claims and claim expenses, net of reinsurance recoverable, as of end of period	11,290,155	9,190,814
Reinsurance recoverable as of end of period	4,706,671	4,319,490	$ 4,710,925
Reserve for claims and claim expenses as of end of period	$ 15,996,826	$ 13,510,304