Fair Value - Level 3 Assets (Details) - Level 3 - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	$ 26,224	$ 11,645
Included in earnings	(92)	(1)
Included in other comprehensive income	(394)	(1,526)
Purchases	3,575	2,030
Sales	(636)	(513)
Transfers into Level 3	3,522	11,452
Transfers out of Level 3	(8,414)	(3,648)
Ending balance	23,785	19,439
Available-for-sale securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	26,224
Included in earnings	(92)
Included in other comprehensive income	(394)
Purchases	3,575
Sales	(636)
Transfers into Level 3	2,432
Transfers out of Level 3	(8,414)
Ending balance	22,695
Corporate debt securities \| Available-for-sale securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	5,825	8,324
Included in earnings	6	7
Included in other comprehensive income	42	(1,378)
Purchases	782	1,718
Sales	(370)	(427)
Transfers into Level 3	1,202	6,895
Transfers out of Level 3	(2,027)	(3,083)
Ending balance	5,460	12,056
Residential mortgage-backed securities \| Available-for-sale securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	937
Included in earnings	(3)
Included in other comprehensive income	(1)
Purchases	0
Sales	(252)
Transfers into Level 3	0
Transfers out of Level 3	(208)
Ending balance	473
Commercial mortgage-backed securities \| Available-for-sale securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	19,462	3,321
Included in earnings	(95)	(8)
Included in other comprehensive income	(437)	(148)
Purchases	2,265	312
Sales	(5)	(86)
Transfers into Level 3	1,230	4,557
Transfers out of Level 3	(6,179)	(565)
Ending balance	16,241	$ 7,383
Other debt securities \| Available-for-sale securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	0
Included in earnings	0
Included in other comprehensive income	2
Purchases	528
Sales	(9)
Transfers into Level 3	0
Transfers out of Level 3	0
Ending balance	521
Nonredeemable preferred stock \| Nonredeemable preferred stock
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	0
Included in earnings	0
Included in other comprehensive income	0
Purchases	0
Sales	0
Transfers into Level 3	1,090
Transfers out of Level 3	0
Ending balance	$ 1,090

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
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
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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

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

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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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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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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-Publisher FASB
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-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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