Investments (Rollforward of Allowance for Credit Loss) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 2,047	$ 6,577	$ 3,347	$ 2,846
Additions for credit losses not previously recorded	947	295	947	4,456
Change in allowance on securities with previous allowance	1,152	(257)	(148)	(687)
Reduction for securities sold during the period	0	(428)	0	(428)
Ending balance	4,146	6,187	4,146	6,187
States, municipalities and territories
Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Beginning balance	0	2,009	0	2,776
Additions for credit losses not previously recorded	0	0	0	0
Change in allowance on securities with previous allowance	0	(175)	0	(942)
Reduction for securities sold during the period	0	0	0	0
Ending balance	0	1,834	0	1,834
Corporate securities
Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Beginning balance	1,914	3,825	3,214	0
Additions for credit losses not previously recorded	0	0	0	3,825
Change in allowance on securities with previous allowance	1,218	(82)	(82)	(82)
Reduction for securities sold during the period	0		0	0
Ending balance	3,132	3,743	3,132	3,743
Commercial mortgage backed securities
Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Beginning balance	0	0	0	0
Additions for credit losses not previously recorded	0	0	0	0
Change in allowance on securities with previous allowance	0	0	0	0
Reduction for securities sold during the period	0		0	0
Ending balance	0	0	0	0
Residential mortgage backed securities
Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Beginning balance	133	743	133	70
Additions for credit losses not previously recorded	0	295	0	631
Change in allowance on securities with previous allowance	(66)	0	(66)	337
Reduction for securities sold during the period	0	(428)	0	(428)
Ending balance	67	610	67	610
Other asset backed securities
Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Beginning balance	0	0	0	0
Additions for credit losses not previously recorded	947	0	947	0
Change in allowance on securities with previous allowance	0	0	0	0
Reduction for securities sold during the period	0		0	0
Ending balance	$ 947	$ 0	$ 947	$ 0

Amount excluding accrued interest, 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).

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 credit loss expense on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) with no credit loss previously recorded.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-9

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Amount, excluding accrued interest, of credit loss expense (reversal of expense) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) with previously recorded allowance and not intended to be sold and not more likely than not will be required to sell before recovery of amortized cost basis.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-9

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

+ References

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Amount, excluding accrued interest, of decrease in 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) from sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-9

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