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Investment Securities - Allowance for Credit Losses HTM (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Beginning balance	$ 307	$ 0
Provision for credit loss expense	66	4
Ending balance, September 30, 2020	373	373
State and political subdivisions
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Beginning balance	95	0
Provision for credit loss expense	(22)	15
Ending balance, September 30, 2020	73	73
Other securities
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Beginning balance	212	0
Provision for credit loss expense	88	(11)
Ending balance, September 30, 2020	$ 300	300
Impact of ASU 2016-13 adoption
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Beginning balance		369
Impact of ASU 2016-13 adoption | State and political subdivisions
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Beginning balance		58
Impact of ASU 2016-13 adoption | Other securities
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Beginning balance		$ 311

X

- Definition

Amount of allowance for credit loss for debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919249-210447

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aaa)
-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121599878&loc=SL82895884-210446

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919249-210447

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X

- Definition

Amount of expense (reversal of expense) for expected credit loss on investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919249-210447

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- Definition

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+ References

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