Fair Value - Level 3 Assets (Details) - Level 3 - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	$ 11,645
Included in earnings	(53)
Included in other comprehensive income	712
Purchases	22,831
Sales	(5,278)
Transfers into Level 3	61,613
Transfers out of Level 3	(65,246)
Ending balance	26,224	$ 11,645
Available-for-sale securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	11,645	12,577
Included in earnings	(204)	5
Included in other comprehensive income	712	141
Purchases	19,995	5,719
Sales	(5,278)	(8,515)
Transfers into Level 3	61,613	18,823
Transfers out of Level 3	(62,259)	(17,105)
Ending balance	26,224	11,645
Corporate debt securities \| Available-for-sale securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	8,324	12,577
Included in earnings	(2)	10
Included in other comprehensive income	(156)	146
Purchases	7,180	2,020
Sales	(1,405)	(7,415)
Transfers into Level 3	10,526	11,542
Transfers out of Level 3	(18,642)	(10,556)
Ending balance	5,825	8,324
Residential mortgage-backed securities \| Available-for-sale securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	0	0
Included in earnings	(19)	4
Included in other comprehensive income	(48)	15
Purchases	287	921
Sales	(1,539)	(32)
Transfers into Level 3	11,496	0
Transfers out of Level 3	(9,240)	(908)
Ending balance	937	0
Commercial mortgage-backed securities \| Available-for-sale securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	3,321	0
Included in earnings	(183)	(9)
Included in other comprehensive income	913	(21)
Purchases	12,281	478
Sales	(2,334)	(1,068)
Transfers into Level 3	39,591	7,281
Transfers out of Level 3	(34,127)	(3,340)
Ending balance	19,462	3,321
Collateralized debt obligations \| Available-for-sale securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	0	0
Included in earnings	0	0
Included in other comprehensive income	3	1
Purchases	247	2,300
Sales	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	(250)	(2,301)
Ending balance	0	0
Nonredeemable preferred stock \| Nonredeemable preferred stock
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	0
Included in earnings	151
Included in other comprehensive income	0
Purchases	2,836
Sales	0
Transfers into Level 3	0
Transfers out of Level 3	(2,987)
Ending balance	$ 0	$ 0

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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
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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).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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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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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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-Publisher FASB
-Name Accounting Standards Codification
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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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