Loans - Impaired Financing Receivables with Related and not Related Allowances (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
With no related allowance recorded:
Average Recorded Investment, Total	$ 29,008	$ 16,633	$ 26,851	$ 17,058
Interest Income Recognized, Total	149	129	408	286
Cash Basis Interest Recognized, Total	149	129	408	286
Commercial, industrial and agricultural
With an allowance recorded:
Average Recorded Investment	2,052	1,273	3,532	1,861
Interest Income Recognized	28	27	45	65
Cash Basis Interest Recognized	28	27	45	65
With no related allowance recorded:
Average Recorded Investment	7,367	3,811	7,196	3,499
Interest Income Recognized	49	32	91	86
Allowance for Loan Losses Allocated	49	32	91	86
Commercial mortgages
With an allowance recorded:
Average Recorded Investment	4,330	7,807	4,330	7,441
Interest Income Recognized	4	46	41	86
Cash Basis Interest Recognized	4	46	41	86
With no related allowance recorded:
Average Recorded Investment	14,684	3,257	11,293	3,767
Interest Income Recognized	66	20	224	38
Allowance for Loan Losses Allocated	66	20	224	38
Residential real estate
With an allowance recorded:
Average Recorded Investment	461	0	462	0
Interest Income Recognized	0	0	5	0
Cash Basis Interest Recognized	0	0	5	0
With no related allowance recorded:
Average Recorded Investment	114	485	38	490
Interest Income Recognized	2	4	2	11
Allowance for Loan Losses Allocated	$ 2	$ 4	$ 2	$ 11

Impaired Financing Receivable, Average Recorded Investment With An Allowance Recorded [Abstract]

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- Definition

Impaired Financing Receivable, Average Recorded Investment With No Allowance Recorded [Abstract]

+ References

No definition available.

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- Definition

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5258-111524

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- Definition

Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

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- Definition

Amount of interest income recognized on a cash-basis method of accounting that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

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Amount of average investment of impaired financing receivables for which there is no related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5258-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524

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Amount of interest income, recognized on accrual basis, on financing receivables that are recognized as impaired, for which there is no related allowance for credit losses.

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Amount of interest income, recognized on cash basis, on financing receivables, for which there is no related allowance for credit losses and are recognized as impaired.

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Amount of interest income, recognized on accrual basis, on financing receivables, for which there is a related allowance for credit losses and are recognized as impaired.

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Amount of interest income on financing receivables, for which there is a related allowance for credit losses, recognized on a cash-basis method of accounting that the financing receivables were impaired.

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