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Investments - Summary of Amortized Cost and Estimated Fair Value of Available-for-Sale Investments, Excluding VIE Investments (Detail) - USD ($) $ in Thousands | Dec. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Debt Securities, Available-for-sale [Line Items] |  |
Fixed income securities, amortized cost | $ 289,712 | $ 341,685
Gross Unrealized Gains | 260 | 643
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments | 5,351 | 6,594
Available-for-sale Securities | 157,020 | 135,224
Debt Securities, Available-for-sale, Allowance for Credit Loss | 0 | 0
Debt Securities, Available-for-Sale, Current | 284,621 | 335,734
Municipal Bonds [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fixed income securities, amortized cost | 14,646 | 9,394
Gross Unrealized Gains | 7 | 13
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments | 570 | 696
Available-for-sale Securities | 14,083 | 8,711
Debt Securities, Available-for-sale, Allowance for Credit Loss | 0 | 0
Corporate Obligations [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fixed income securities, amortized cost | 92,990 | 92,694
Gross Unrealized Gains | 107 | 262
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments | 3,905 | 4,965
Available-for-sale Securities | 89,192 | 87,991
Debt Securities, Available-for-sale, Allowance for Credit Loss | 0 | 0
U.S. Government Obligations [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fixed income securities, amortized cost | 41,706 | 39,091
Gross Unrealized Gains | 98 | 364
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments | 809 | 933
Available-for-sale Securities | 40,995 | 38,522
Debt Securities, Available-for-sale, Allowance for Credit Loss | 0 | 0
Residential Mortgage-Backed Securities [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fixed income securities, amortized cost | 2,475 | 0
Gross Unrealized Gains | 0 | 0
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments | 29 | 0
Available-for-sale Securities | 2,446 | 0
Debt Securities, Available-for-sale, Allowance for Credit Loss | 0 | 0
Collateralized Debt Obligations [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fixed income securities, amortized cost | 3,131 | 0
Gross Unrealized Gains | 13 | 0
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments | 2 | 0
Available-for-sale Securities | 3,142 | 0
Debt Securities, Available-for-sale, Allowance for Credit Loss | 0 | 0
Asset-backed Securities [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fixed income securities, amortized cost | 5,049 | 0
Gross Unrealized Gains | 14 | 0
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments | 2 | 0
Available-for-sale Securities | 5,061 | 0
Debt Securities, Available-for-sale, Allowance for Credit Loss | 0 | 0
Short-term Investments [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fixed income securities, amortized cost | 127,588 | 200,506
Gross Unrealized Gains | 13 | 4
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments | 0 | 0
Available-for-sale Securities | 127,601 | 200,510
Debt Securities, Available-for-sale, Allowance for Credit Loss | 0 | 0
Commercial Mortgage Backed Securities [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fixed income securities, amortized cost | 2,127 |
Gross Unrealized Gains | 8 | 0
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments | 34 | 0
Available-for-sale Securities | 2,101 | 0
Debt Securities, Available-for-sale, Allowance for Credit Loss | 0 | 0
Collateralized Mortgage Backed Securities [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fixed income securities, amortized cost | 2,127 | 0
Long-Term Investments |  |
Debt Securities, Available-for-sale [Line Items] |  |
Gross Unrealized Gains | 247 | 639
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments | 5,351 | 6,594
Available-for-sale Securities | 157,020 | 135,224
Debt Securities, Available-for-sale, Allowance for Credit Loss | 0 | 0
Long-Term Investments | Fixed Income Investments And Other Investments [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fixed income securities, amortized cost | $ 162,124 | $ 141,179

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