Fair Value Measurements - Reconciliation of activity for assets and liabilities measured at fair value (Details) - Fair Value, Inputs, Level 3 - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2020	Dec. 31, 2019
Assets:
Assets - Beginning balance	$ 11,211	$ 10,023
Realized (loss) gain included in earnings	5,735	31
Unrealized gain included in other comprehensive income	0	131
Purchases of available -for-sale securities	0	4,030
Principal redemption	0	3,004
Migrated to Level 2 valuation	(9,233)
Assets - Ending balance	7,713	11,211
Liabilities:
Liabilities - Beginning balance	66	269
Realized loss (gain) included in earnings	(66)	203
Principal redemption	0	0
Liabilities - Ending balance	0	66
Other equity investments
Assets:
Assets - Beginning balance	10,931	9,794
Realized (loss) gain included in earnings	0	(20)
Unrealized gain included in other comprehensive income	0	131
Purchases of available -for-sale securities	0	4,030
Principal redemption	0	3,004
Migrated to Level 2 valuation	(9,233)
Assets - Ending balance	1,698	10,931
Liabilities:
Liabilities - Beginning balance	0	0
Realized loss (gain) included in earnings		0
Principal redemption	0	0
Liabilities - Ending balance	0	0
Mortgage Banking Derivatives
Assets:
Assets - Beginning balance	280	229
Realized (loss) gain included in earnings	5,735	51
Assets - Ending balance	6,015	280
Liabilities:
Liabilities - Beginning balance	66	269
Realized loss (gain) included in earnings	(66)	203
Principal redemption	0	0
Liabilities - Ending balance	$ 0	$ 66

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

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

+ References

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

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(3)
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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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- Definition

Amount of gain (loss) recognized in income from liability measured at fair value on recurring basis using unobservable input (level 3).

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Amount of settlements of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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