Fair Value - Level 3 Assets (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022
Roll forward of level 3 fair value measurements on a recurring basis
Fair value, asset, recurring basis, unobservable input reconciliation, asset, gain (loss), statement of other comprehensive income or comprehensive income	Other comprehensive income (loss)	Other comprehensive income (loss)
Fair value, asset, recurring basis, unobservable input reconciliation, gain (loss), statement of income or comprehensive income	Net investment income	Net realized and unrealized investment (losses) gains
Level 3
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	$ 22,559	$ 31,881
Included in earnings	(732)	(2,055)
Included in other comprehensive income (loss)	721	(3,520)
Purchases	10,349	13,177
Sales	(2,277)	(18,864)
Transfers into Level 3	14,408	60,635
Transfers out of Level 3	(20,660)	(58,695)
Ending balance	24,368	22,559
Available-for-sale securities \| Level 3
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	18,780	29,798
Included in earnings	(779)	(1,751)
Included in other comprehensive income (loss)	721	(3,520)
Purchases	6,891	11,177
Sales	(2,277)	(18,864)
Transfers into Level 3	12,551	60,635
Transfers out of Level 3	(18,853)	(58,695)
Ending balance	17,034	18,780
Available-for-sale securities \| Level 3 \| Corporate debt securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	3,686	5,256
Included in earnings	4	2
Included in other comprehensive income (loss)	314	(437)
Purchases	4,316	6,290
Sales	(1,536)	(4,810)
Transfers into Level 3	5,611	9,689
Transfers out of Level 3	(7,889)	(12,304)
Ending balance	4,506	3,686
Available-for-sale securities \| Level 3 \| Commercial mortgage-backed securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	10,910	15,728
Included in earnings	(778)	(1,060)
Included in other comprehensive income (loss)	311	(1,132)
Purchases	2,575	0
Sales	(621)	(3,825)
Transfers into Level 3	5,373	11,494
Transfers out of Level 3	(6,776)	(10,295)
Ending balance	10,994	10,910
Available-for-sale securities \| Level 3 \| Residential mortgage-backed securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	4,184	8,814
Included in earnings	(5)	(693)
Included in other comprehensive income (loss)	96	(1,951)
Purchases	0	4,887
Sales	(120)	(10,229)
Transfers into Level 3	1,567	39,452
Transfers out of Level 3	(4,188)	(36,096)
Ending balance	1,534	4,184
Equity securities \| Level 3 \| Equity securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	3,779	2,083
Included in earnings	47	(304)
Included in other comprehensive income (loss)	0	0
Purchases	3,458	2,000
Sales	0	0
Transfers into Level 3	1,857	0
Transfers out of Level 3	(1,807)	0
Ending balance	$ 7,334	$ 3,779

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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- Definition

Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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- Definition

Amount of gain (loss) recognized in other comprehensive income (OCI) from asset measured at fair value on recurring basis using unobservable input (level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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- Definition

Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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Amount of sale of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of transfer of financial instrument classified as an asset into level 3 of the fair value hierarchy.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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- Definition

Amount of transfers of financial instrument classified as an asset out of level 3 of the fair value hierarchy.

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Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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-Topic 820
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- Definition

Indicates line item in statement in which net income is reported that includes gain (loss) from asset measured at fair value using unobservable input (level 3).

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