Fair Value Measurements - Reconciliation of activity for assets and liabilities measured at fair value (Details) - Fair Value, Inputs, Level 3 - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2020	Dec. 31, 2019
Assets - Beginning balance	$ 11,211	$ 10,023
Realized (loss) gain included in earnings	51	31
Unrealized gain included in other comprehensive income	694	131
Purchases of available -for-sale securities	41,557	4,030
Principal redemption		(3,004)
Assets - Ending balance	53,513	11,211
Liabilities - Beginning balance	66	269
Realized loss (gain) included in earnings	1,536	(203)
Liabilities - Ending balance	1,602	66
Other equity investments
Assets - Beginning balance	10,931	9,794
Realized (loss) gain included in earnings		(20)
Unrealized gain included in other comprehensive income	694	131
Purchases of available -for-sale securities	41,557	4,030
Principal redemption		(3,004)
Assets - Ending balance	53,182	10,931
Mortgage Banking Derivatives
Assets - Beginning balance	280	229
Realized (loss) gain included in earnings	51	51
Assets - Ending balance	331	280
Liabilities - Beginning balance	66	269
Realized loss (gain) included in earnings	1,536	(203)
Liabilities - Ending balance	$ 1,602	$ 66

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

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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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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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.

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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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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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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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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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