Fair Value (Activity Under Level 3, Fair Value Measurements Using Significant Unobservable Inputs By Asset Type) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Market Value [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance fixed maturities	$ 1,525,734	$ 1,023,838	$ 1,330,224	$ 772,979
Total gains or (losses) (realized/unrealized) Included in earnings	(75)	845	(19,447)	411
Total gains or (losses) (realized/unrealized) Included in other comprehensive income (loss)	(1,726)	4,162	10,131	2,426
Purchases, issuances and settlements	279,051	102,364	482,076	359,211
Transfer in and/or (out) of Level 3		3,326		(492)
Ending balance	1,802,984	1,134,535	1,802,984	1,134,535
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date	(2,003)		(24,197)	(539)
Market Value [Member] \| Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance fixed maturities	705,571	721,834	701,492	617,588
Total gains or (losses) (realized/unrealized) Included in earnings	3,184	362	(12,366)	(100)
Total gains or (losses) (realized/unrealized) Included in other comprehensive income (loss)	(1,311)	(992)	6,107	(4,898)
Purchases, issuances and settlements	86,597	(1,349)	98,808	112,060
Transfer in and/or (out) of Level 3		4,189		(606)
Ending balance	794,041	724,044	794,041	724,044
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date	761		(16,518)	(539)
Market Value [Member] \| Asset Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance fixed maturities	815,276	295,730	623,033	153,641
Total gains or (losses) (realized/unrealized) Included in earnings	(3,292)	457	(7,254)	582
Total gains or (losses) (realized/unrealized) Included in other comprehensive income (loss)	(381)	5,028	4,094	7,238
Purchases, issuances and settlements	192,466	103,574	384,196	243,328
Transfer in and/or (out) of Level 3
Ending balance	1,004,069	404,789	1,004,069	404,789
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date	(2,764)		(7,679)
Market Value [Member] \| Foreign Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance fixed maturities	4,887	6,274	5,699	1,750
Total gains or (losses) (realized/unrealized) Included in earnings	33	26	173	(71)
Total gains or (losses) (realized/unrealized) Included in other comprehensive income (loss)	(34)	126	(70)	86
Purchases, issuances and settlements	(12)	139	(928)	3,823
Transfer in and/or (out) of Level 3		(863)		114
Ending balance	4,875	5,702	4,875	5,702
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date
Fair Value [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance fixed maturities		4,431		5,826
Total gains or (losses) (realized/unrealized) Included in earnings		1,371		(24)
Total gains or (losses) (realized/unrealized) Included in other comprehensive income (loss)
Purchases, issuances and settlements		(2,054)		(2,054)
Transfer in and/or (out) of Level 3
Ending balance		3,748		3,748
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date
Fair Value [Member] \| Foreign Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance fixed maturities		4,431		5,826
Total gains or (losses) (realized/unrealized) Included in earnings		1,371		(24)
Total gains or (losses) (realized/unrealized) Included in other comprehensive income (loss)
Purchases, issuances and settlements		(2,054)		(2,054)
Transfer in and/or (out) of Level 3
Ending balance		3,748		3,748
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date

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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
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Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Amount of gain (loss) recognized in other comprehensive income (OCI) from asset measured at fair value on recurring basis using unobservable input (level 3).

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Amount of purchases, (sales), issuances and (settlements) 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 (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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