Allowance for Loan Losses and Credit Quality of Loans, Additional Information on Loans Specifically Evaluated for Impairment (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Allowance for Loan Losses and Credit Quality of Loans [Abstract]
Threshold balance for classified loans to be evaluated individually for impairment	$ 750
Total Loans [Abstract]
Recorded investment balance (book)	20,578	$ 21,138
Unpaid principal balance (legal)	28,552	28,120
Related allowance	25	57
Originated Loans [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	20,345	20,115
Unpaid principal balance (legal)	28,314	27,041
Originated Loans [Member] \| Commercial Loans [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	5,553	4,853
Unpaid principal balance (legal)	8,828	7,878
With an allowance recorded [Abstract]
Recorded investment balance (book)	233	1,023
Unpaid principal balance (legal)	238	1,079
Total Loans [Abstract]
Related allowance	25	57
Originated Loans [Member] \| Commercial Loans [Member] \| C&I [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	228	0
Unpaid principal balance (legal)	497	0
With an allowance recorded [Abstract]
Recorded investment balance (book)	233	0
Unpaid principal balance (legal)	238	0
Total Loans [Abstract]
Related allowance	25	0
Originated Loans [Member] \| Commercial Loans [Member] \| CRE [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	4,312	0
Unpaid principal balance (legal)	6,330	0
Originated Loans [Member] \| Commercial Loans [Member] \| Commercial [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	0	0
Unpaid principal balance (legal)	0	251
Originated Loans [Member] \| Commercial Loans [Member] \| Commercial Real Estate [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	0	1,526
Unpaid principal balance (legal)	0	3,244
With an allowance recorded [Abstract]
Recorded investment balance (book)	0	761
Unpaid principal balance (legal)	0	817
Total Loans [Abstract]
Related allowance	0	30
Originated Loans [Member] \| Commercial Loans [Member] \| Agricultural [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	0	217
Unpaid principal balance (legal)	0	230
With an allowance recorded [Abstract]
Recorded investment balance (book)	0	262
Unpaid principal balance (legal)	0	262
Total Loans [Abstract]
Related allowance	0	27
Originated Loans [Member] \| Commercial Loans [Member] \| Agricultural Real Estate [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	0	2,250
Unpaid principal balance (legal)	0	2,423
Originated Loans [Member] \| Commercial Loans [Member] \| Business Banking [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	1,013	860
Unpaid principal balance (legal)	2,001	1,730
Originated Loans [Member] \| Consumer Loans [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	7,887	8,432
Unpaid principal balance (legal)	10,072	10,383
Originated Loans [Member] \| Consumer Loans [Member] \| Dealer Finance [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	143	0
Unpaid principal balance (legal)	241	0
Originated Loans [Member] \| Consumer Loans [Member] \| Direct [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	7,744
Unpaid principal balance (legal)	9,831
Originated Loans [Member] \| Consumer Loans [Member] \| Indirect [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	0	131
Unpaid principal balance (legal)	0	143
Originated Loans [Member] \| Consumer Loans [Member] \| Home Equity [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	0	8,027
Unpaid principal balance (legal)	0	9,966
Originated Loans [Member] \| Consumer Loans [Member] \| Direct [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)		274
Unpaid principal balance (legal)		274
Originated Loans [Member] \| Residential Real Estate [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	6,905	6,830
Unpaid principal balance (legal)	$ 9,414	$ 8,780

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The threshold balance for classified loans to be individually evaluated for impairment.

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Amount of allowance for credit losses related to recorded investment.

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