Loans - Impaired Financing Receivables with Related and not Related Allowances (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
With no related allowance recorded:
Average Recorded Investment, Total	$ 25,825	$ 17,366
Interest Income Recognized, Total	259	157
Cash Basis Interest Recognized, Total	259	157
Commercial, industrial and agricultural
With an allowance recorded:
Average Recorded Investment	4,272	2,158
Interest Income Recognized	17	38
Cash Basis Interest Recognized	17	38
With no related allowance recorded:
Average Recorded Investment	7,161	3,376
Interest Income Recognized	42	54
Cash Basis Interest Recognized	42	54
Commercial mortgages
With an allowance recorded:
Average Recorded Investment	4,331	7,267
Interest Income Recognized	37	40
Cash Basis Interest Recognized	37	40
With no related allowance recorded:
Average Recorded Investment	9,598	4,065
Interest Income Recognized	158	18
Cash Basis Interest Recognized	158	18
Residential real estate
With an allowance recorded:
Average Recorded Investment	463	0
Interest Income Recognized	5	0
Cash Basis Interest Recognized	5	0
With no related allowance recorded:
Average Recorded Investment	0	500
Interest Income Recognized	0	7
Cash Basis Interest Recognized	$ 0	$ 7

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=118936363&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=118936363&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.

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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=118936363&loc=d3e5258-111524

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=118936363&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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