Reserve for Claims and Claim Expenses - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Claims and claim expenses recovered	$ 1,512,300,000	$ 2,029,529,000	$ 968,595,000
Reinsurance balances payable
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Aggregate deposit liabilities	4,000,000	4,200,000
Deposit Contracts, Underwriting Risk Only
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Claims and claim expenses recovered	200,000	200,000	400,000
Deposit Contracts, Timing Risk Only
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Increase in other income related to assumed reinsurance contracts	$ 0	$ 0	$ 1,000,000