Allowance for Loan Losses and Credit Quality of Loans, Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Allowance for Loan Losses and Credit Quality of Loans [Abstract]
Threshold balance for classified loans to be evaluated individually for impairment	$ 800
With an allowance recorded [Abstract]
Recorded investment balance (book)	25,309		$ 28,874
Unpaid principal balance (legal)	27,351		31,582
Related allowance	422		1,517
Average recorded investment	25,672	$ 33,374
Interest income recognized	206	324
Originated Loans [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	24,141		21,912
Unpaid principal balance (legal)	26,183		24,321
With an allowance recorded [Abstract]
Average recorded investment	25,371	32,169
Interest income recognized	206	324
Originated Loans [Member] \| Commercial Loans [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	9,568		7,313
Unpaid principal balance (legal)	9,868		7,970
With an allowance recorded [Abstract]
Recorded investment balance (book)	1,168		5,757
Unpaid principal balance (legal)	1,168		5,940
Related allowance	422		826
Originated Loans [Member] \| Commercial Loans [Member] \| Commercial [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	3,495		1,278
Unpaid principal balance (legal)	3,536		1,697
With an allowance recorded [Abstract]
Average recorded investment	2,926	2,773
Interest income recognized	0	19
Originated Loans [Member] \| Commercial Loans [Member] \| Commercial Real Estate [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	3,778		3,816
Unpaid principal balance (legal)	3,810		3,841
With an allowance recorded [Abstract]
Recorded investment balance (book)	1,081		5,553
Unpaid principal balance (legal)	1,081		5,736
Related allowance	335		735
Average recorded investment	5,995	13,509
Interest income recognized	44	100
Originated Loans [Member] \| Commercial Loans [Member] \| Agricultural [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	130		130
Unpaid principal balance (legal)	138		137
With an allowance recorded [Abstract]
Recorded investment balance (book)	37		49
Unpaid principal balance (legal)	37		49
Related allowance	37		37
Average recorded investment	173	158
Interest income recognized	0	0
Originated Loans [Member] \| Commercial Loans [Member] \| Agricultural Real Estate [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	1,520		1,434
Unpaid principal balance (legal)	1,660		1,567
With an allowance recorded [Abstract]
Recorded investment balance (book)	50		155
Unpaid principal balance (legal)	50		155
Related allowance	50		54
Average recorded investment	1,580	616
Interest income recognized	11	11
Originated Loans [Member] \| Commercial Loans [Member] \| Business Banking [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	645		655
Unpaid principal balance (legal)	724		728
With an allowance recorded [Abstract]
Average recorded investment	650	978
Interest income recognized	2	6
Originated Loans [Member] \| Consumer Loans [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	8,379		8,488
Unpaid principal balance (legal)	9,287		9,445
Originated Loans [Member] \| Consumer Loans [Member] \| Indirect [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	5		5
Unpaid principal balance (legal)	15		16
With an allowance recorded [Abstract]
Average recorded investment	5	11
Interest income recognized	0	0
Originated Loans [Member] \| Consumer Loans [Member] \| Home Equity [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	8,374		8,483
Unpaid principal balance (legal)	9,272		9,429
With an allowance recorded [Abstract]
Average recorded investment	8,431	8,003
Interest income recognized	110	121
Originated Loans [Member] \| Residential Real Estate Mortgages [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	6,194		6,111
Unpaid principal balance (legal)	7,028		6,906
With an allowance recorded [Abstract]
Average recorded investment	5,611	6,121
Interest income recognized	39	67
Acquired Loans [Member]
With an allowance recorded [Abstract]
Average recorded investment	301	1,205
Interest income recognized	0	0
Acquired Loans [Member] \| Commercial Loans [Member]
With an allowance recorded [Abstract]
Recorded investment balance (book)	0		1,205
Unpaid principal balance (legal)	0		1,321
Related allowance	0		691
Acquired Loans [Member] \| Commercial Loans [Member] \| Commercial Real Estate [Member]
With an allowance recorded [Abstract]
Recorded investment balance (book)	0		1,205
Unpaid principal balance (legal)	0		1,321
Related allowance	0		$ 691
Average recorded investment	301	1,205
Interest income recognized	$ 0	$ 0

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

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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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5212-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5258-111524

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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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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953550-111524

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Amount of allowance for credit losses related to recorded investment.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Recorded Investment
-URI http://asc.fasb.org/extlink&oid=65880944

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
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-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5212-111524

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