Fair Value Measurements - Additional Information (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Derivative Credit Risk Valuation Adjustment, Derivative Liabilities	$ 283	$ 19
Derivative liabilities	$ 37,000	$ 38,000
Weighted average discounted rate of estimated future premium payments to be paid by the VIEs	3.10%	3.00%
Derivative assets	$ 26,000	$ 27,000
Derivative assets	26,000	28,000
Warrants [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Derivative assets	1,000	1,000
Fair Value Measured at Net Asset Value Per Share [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Other investments	$ 449,000	$ 494,000
Fixed Income Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Percentage of investment portfolio valued using dealer quotes	2.00%	5.00%
Minimum [Member] | Fixed Income Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Percentage of investment portfolio valued using internal valuation models	4.00%	4.00%
Maximum [Member] | Fixed Income Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Percentage of investment portfolio valued using external pricing services	94.00%	91.00%
Variable Interest Entity, Primary Beneficiary [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Derivative liabilities	$ 1,106,000	$ 1,048,000
Weighted average discounted rate of estimated future premium payments to be paid by the VIEs	7.50%	6.80%
Derivative assets	$ 224,000	$ 239,000
Derivative assets	$ 224,000	$ 239,000