Allowance for Expected Credit Losses - Reinsurance recoverables (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Credit Loss [Abstract]
Balance at beginning of period	$ 5,880,735	$ 4,500,802
Balance at end of period	6,563,654	5,880,735
Allowance for Expected Credit Losses
Balance at beginning of period	13,230	11,636
Change for provision of expected credit losses	8,314	1,594
Balance at end of period	$ 21,544	$ 13,230