Fair Value Measurement (Level 3 Assets) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation:
Beginning balance	$ 11,157	$ 8,175
Included in earnings, as a part of:
Included in other comprehensive income	(205)	160
Purchases	3,422	1,305
Sales	(1,707)	(142)
Transfers in	1,550	1,200
Transfers out	(2,320)	(2,151)
Ending balance	11,675	8,431
Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets held at period-end	(222)	0
Net investment income
Included in earnings, as a part of:
Total gains (losses) realized and unrealized, included in earnings	0	(116)
Net realized investment gains (losses)
Included in earnings, as a part of:
Total gains (losses) realized and unrealized, included in earnings	(222)	0
Corporate Debt
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation:
Beginning balance	5,079	4,322
Included in earnings, as a part of:
Included in other comprehensive income	(83)	3
Purchases	0	1,305
Sales	(1,707)	(136)
Transfers in	945	0
Transfers out	(794)	(1,200)
Ending balance	3,440	4,296
Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets held at period-end	0	0
Corporate Debt \| Net investment income
Included in earnings, as a part of:
Total gains (losses) realized and unrealized, included in earnings	0	2
Corporate Debt \| Net realized investment gains (losses)
Included in earnings, as a part of:
Total gains (losses) realized and unrealized, included in earnings	0	0
Asset-backed Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation:
Beginning balance	2,992	3,850
Included in earnings, as a part of:
Included in other comprehensive income	(122)	157
Purchases	3,422	0
Sales	0	(6)
Transfers in	605	1,200
Transfers out	0	(951)
Ending balance	6,897	4,132
Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets held at period-end	0	0
Asset-backed Securities \| Net investment income
Included in earnings, as a part of:
Total gains (losses) realized and unrealized, included in earnings	0	(118)
Asset-backed Securities \| Net realized investment gains (losses)
Included in earnings, as a part of:
Total gains (losses) realized and unrealized, included in earnings	0	0
Other investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation:
Beginning balance	3,086	3
Included in earnings, as a part of:
Included in other comprehensive income	0	0
Purchases	0	0
Sales	0	0
Transfers in	0	0
Transfers out	(1,526)	0
Ending balance	1,338	3
Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets held at period-end	(222)	0
Other investments \| Net investment income
Included in earnings, as a part of:
Total gains (losses) realized and unrealized, included in earnings	0	0
Other investments \| Net realized investment gains (losses)
Included in earnings, as a part of:
Total gains (losses) realized and unrealized, included in earnings	$ (222)	$ 0

Included in Earnings, as a part of.

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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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.

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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
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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

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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

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-Publisher FASB
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-Section 50
-Paragraph 2
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- Definition

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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- Definition

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

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
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- Definition

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

+ References

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-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
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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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