Fair Value - Level 3 Assets (Details) - Level 3 - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	$ 19,439		$ 11,645
Included in earnings	(61)		(62)
Included in other comprehensive income	1,147		(379)
Purchases	8,741		10,771
Sales	(316)		(829)
Transfers into Level 3	5,476		16,928
Transfers out of Level 3	(10,390)		(14,038)
Ending balance	24,036		24,036
Available-for-sale securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	19,439	$ 13,620	11,645	$ 12,577
Included in earnings	(36)	(1)	(37)	8
Included in other comprehensive income	1,147	30	(379)	298
Purchases	7,921	0	9,951	2,133
Sales	(316)	(6,932)	(829)	(7,369)
Transfers into Level 3	5,476	5,132	16,928	10,651
Transfers out of Level 3	(10,390)	(2,925)	(14,038)	(9,374)
Ending balance	23,241	8,924	23,241	8,924
Corporate debt securities \| Available-for-sale securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	12,056	11,523	8,324	12,577
Included in earnings	(2)	(20)	5	(9)
Included in other comprehensive income	867	23	(511)	291
Purchases	783	0	2,501	734
Sales	(115)	(5,841)	(542)	(6,272)
Transfers into Level 3	1,142	2,581	8,037	7,394
Transfers out of Level 3	(9,815)	(1,893)	(12,898)	(8,342)
Ending balance	4,916	6,373	4,916	6,373
Residential mortgage-backed securities \| Available-for-sale securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance		915		0
Included in earnings		4		4
Included in other comprehensive income		15		15
Purchases		0		921
Sales		(26)		(32)
Transfers into Level 3		0		0
Transfers out of Level 3		(908)		(908)
Ending balance		0		0
Commercial mortgage-backed securities \| Available-for-sale securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	7,383	1,182	3,321	0
Included in earnings	(34)	15	(42)	13
Included in other comprehensive income	268	(8)	120	(8)
Purchases	6,891	0	7,203	478
Sales	(201)	(1,065)	(287)	(1,065)
Transfers into Level 3	4,334	2,551	8,891	3,257
Transfers out of Level 3	(575)	(124)	(1,140)	(124)
Ending balance	18,066	$ 2,551	18,066	$ 2,551
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	12		12
Purchases	247		247
Sales	0		0
Transfers into Level 3	0		0
Transfers out of Level 3	0		0
Ending balance	259		259
Nonredeemable preferred stock \| Nonredeemable preferred stock
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	0		0
Included in earnings	(25)		(25)
Included in other comprehensive income	0		0
Purchases	820		820
Sales	0		0
Transfers into Level 3	0		0
Transfers out of Level 3	0		0
Ending balance	$ 795		$ 795

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

No definition available.

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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)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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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.

+ References

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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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- Definition

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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-Topic 820
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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