Investments - Schedule of Amortized Cost and Fair Value of Fixed maturity Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2026	Dec. 31, 2025
Marketable Securities [Line Items]
Amortized Cost	$ 1,678,981	$ 1,364,228
Gross Unrealized Gains	293	15,097
Gross Unrealized Losses	(56,383)	(8,319)
Fair Value	1,622,891	1,371,006
U.S. government and government agency
Marketable Securities [Line Items]
Amortized Cost	47,766	80,184
Gross Unrealized Gains	12	184
Gross Unrealized Losses	(319)	0
Fair Value	47,459	80,368
State and municipal
Marketable Securities [Line Items]
Amortized Cost	213,856	131,607
Gross Unrealized Gains	28	713
Gross Unrealized Losses	(11,137)	(3,042)
Fair Value	202,747	129,278
Commercial mortgage-backed securities
Marketable Securities [Line Items]
Amortized Cost	171,143	170,496
Gross Unrealized Gains	49	1,688
Gross Unrealized Losses	(5,835)	(862)
Fair Value	165,357	171,322
Residential mortgage-backed securities
Marketable Securities [Line Items]
Amortized Cost	325,799	317,905
Gross Unrealized Gains	141	4,071
Gross Unrealized Losses	(14,235)	(3,415)
Fair Value	311,705	318,561
Asset-backed securities
Marketable Securities [Line Items]
Amortized Cost	225,703	168,363
Gross Unrealized Gains	53	931
Gross Unrealized Losses	(4,578)	(290)
Fair Value	221,178	169,004
Corporate
Marketable Securities [Line Items]
Amortized Cost	694,714	495,673
Gross Unrealized Gains	10	7,510
Gross Unrealized Losses	(20,279)	(710)
Fair Value	$ 674,445	$ 502,473

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on 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 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) 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
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

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+ References

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

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Amount excluding accrued interest, of 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 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477657/942-210-S45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Paragraph 1
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-URI https://asc.fasb.org/1943274/2147478478/942-210-S50-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
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-Name Accounting Standards Codification
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-Paragraph 1
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

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