Investments - Schedule of Amortized Cost and Estimated Fair Value f Available-For-Sale Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Amortized Cost	$ 206,096	$ 214,505
Allowance for Credit Loss	0	0
Gross Unrealized Gains	497	426
Gross Unrealized Losses	(361)	(886)
Estimated Fair Value	206,232	214,045
U.S. Treasury and U.S. government agencies [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Amortized Cost	56,560	75,532
Allowance for Credit Loss	0	0
Gross Unrealized Gains	6	0
Gross Unrealized Losses	(86)	(298)
Estimated Fair Value	56,480	75,234
Corporate debt securities [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Amortized Cost	129,481	109,174
Allowance for Credit Loss	0	0
Gross Unrealized Gains	326	164
Gross Unrealized Losses	(239)	(548)
Estimated Fair Value	129,568	108,790
Asset-backed securities [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Amortized Cost	20,055	29,799
Allowance for Credit Loss	0	0
Gross Unrealized Gains	165	262
Gross Unrealized Losses	(36)	(40)
Estimated Fair Value	20,184	30,021
Total fixed maturity securities [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Amortized Cost	206,096	214,505
Allowance for Credit Loss	0	0
Gross Unrealized Gains	497	426
Gross Unrealized Losses	(361)	(886)
Estimated Fair Value	$ 206,232	$ 214,045

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(1))
-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
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-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479130/326-30-45-1

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Amount of allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
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-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Amount of cumulative unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity) and investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
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-URI https://asc.fasb.org/1943274/2147481800/320-10-50-5A

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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Amount of cumulative unrecognized loss on investment in debt security measured at amortized cost (held-to-maturity) and investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
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Fair value of investment in debt security measured at amortized cost (held-to-maturity) and investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
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+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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