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Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Thousands | Dec. 31, 2021 | Dec. 31, 2020
--- | --- | ---
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items] |  |
Other Investments | $ 690,000 | $ 595,000
Credit valuation adjustment included in fair value of credit derivative liabilities | 32 | 19
Fair value of derivative liabilities | 93,000 |
Derivative liabilities | $ 95,000 | $ 114,000
Weighted average discounted rate of estimated future premium payments to be paid by the VIEs | 2.20% | 2.20%
Number of Credit Risk Derivatives Held | 1 |
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 | 6.00% | 2.00%
Asset-backed Securities [Member] |  |
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items] |  |
Coupon rate | 5.97% | 5.97%
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% | 3.00%
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 | 90.00% | 95.00%
Variable Interest Entity, Primary Beneficiary [Member] |  |
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items] |  |
Fair value of derivative liabilities | $ 0 |
Derivative liabilities | $ 1,940,000 | $ 1,835,000
Weighted average discounted rate of estimated future premium payments to be paid by the VIEs | 3.00% | 2.40%
Real Estate [Member] |  |
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items] |  |
Other Investments | $ 33,000 | $ 16,000
Hedge Funds, Multi-strategy [Member] |  |
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items] |  |
Other Investments | 216,000 | 196,000
Interest Rate Contract [Member] |  |
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items] |  |
Other Investments | 78,000 | 78,000
Illiquid Investments [Member] |  |
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items] |  |
Other Investments | $ 88,000 | $ 65,000

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