Allowance for Loan Losses and Credit Quality of Loans, Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Allowance for Loan Losses and Credit Quality of Loans [Abstract]
Threshold balance for classified loans to be evaluated individually for impairment	$ 800		$ 800
With an allowance recorded [Abstract]
Recorded investment balance (book)	37,389		37,389		$ 27,168
Unpaid principal balance (legal)	41,760		41,760		31,665
Related allowance	3,372		3,372		2,005
Average recorded investment	36,521	$ 35,142	35,116	$ 33,980
Interest income recognized	251	269	731	694
Originated Loans [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	27,488		27,488		21,296
Unpaid principal balance (legal)	29,887		29,887		23,828
With an allowance recorded [Abstract]
Average recorded investment	35,316	25,693	33,911	24,252
Interest income recognized	251	269	731	694
Originated Loans [Member] \| Commercial Loans [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	12,898		12,898		7,586
Unpaid principal balance (legal)	13,497		13,497		8,606
With an allowance recorded [Abstract]
Recorded investment balance (book)	8,696		8,696		4,667
Unpaid principal balance (legal)	10,552		10,552		6,516
Related allowance	2,681		2,681		1,270
Originated Loans [Member] \| Commercial Loans [Member] \| Commercial [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	2,174		2,174		2,244
Unpaid principal balance (legal)	2,441		2,441		2,490
With an allowance recorded [Abstract]
Recorded investment balance (book)	1,014		1,014		457
Unpaid principal balance (legal)	1,022		1,022		457
Related allowance	555		555		300
Average recorded investment	3,204	2,469	3,041	2,026
Interest income recognized	0	42	0	128
Originated Loans [Member] \| Commercial Loans [Member] \| Commercial Real Estate [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	8,469		8,469		3,165
Unpaid principal balance (legal)	8,602		8,602		3,175
With an allowance recorded [Abstract]
Recorded investment balance (book)	7,476		7,476		4,210
Unpaid principal balance (legal)	9,324		9,324		6,059
Related allowance	2,035		2,035		970
Average recorded investment	15,799	8,560	14,782	8,884
Interest income recognized	48	42	122	124
Originated Loans [Member] \| Commercial Loans [Member] \| Agricultural [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	133		133		576
Unpaid principal balance (legal)	139		139		1,164
With an allowance recorded [Abstract]
Recorded investment balance (book)	50		50		0
Unpaid principal balance (legal)	50		50		0
Related allowance	37		37		0
Average recorded investment	85	19	101	19
Interest income recognized	0	0	1	1
Originated Loans [Member] \| Commercial Loans [Member] \| Agricultural Real Estate [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	1,457		1,457		618
Unpaid principal balance (legal)	1,583		1,583		744
With an allowance recorded [Abstract]
Recorded investment balance (book)	156		156		0
Unpaid principal balance (legal)	156		156		0
Related allowance	54		54		0
Average recorded investment	935	626	742	630
Interest income recognized	11	11	33	34
Originated Loans [Member] \| Commercial Loans [Member] \| Business Banking [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	665		665		983
Unpaid principal balance (legal)	732		732		1,033
With an allowance recorded [Abstract]
Average recorded investment	743	1,003	882	952
Interest income recognized	0	3	7	9
Originated Loans [Member] \| Consumer Loans [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	8,502		8,502		7,693
Unpaid principal balance (legal)	9,480		9,480		8,595
Originated Loans [Member] \| Consumer Loans [Member] \| Indirect [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	7		7		12
Unpaid principal balance (legal)	17		17		21
With an allowance recorded [Abstract]
Average recorded investment	8	20	9	14
Interest income recognized	0	0	0	0
Originated Loans [Member] \| Consumer Loans [Member] \| Home Equity [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	8,495		8,495		7,681
Unpaid principal balance (legal)	9,463		9,463		8,574
With an allowance recorded [Abstract]
Average recorded investment	8,401	7,432	8,207	6,869
Interest income recognized	116	134	357	298
Originated Loans [Member] \| Consumer Loans [Member] \| Direct [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	0		0		0
Unpaid principal balance (legal)	0		0		0
With an allowance recorded [Abstract]
Average recorded investment	0	0	0	1
Interest income recognized	0	0	0	0
Originated Loans [Member] \| Residential Real Estate Mortgages [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	6,088		6,088		6,017
Unpaid principal balance (legal)	6,910		6,910		6,627
With an allowance recorded [Abstract]
Average recorded investment	6,141	5,564	6,147	4,857
Interest income recognized	76	37	211	100
Acquired Loans [Member]
With an allowance recorded [Abstract]
Average recorded investment	1,205	9,449	1,205	9,728
Interest income recognized	0	0	0	0
Acquired Loans [Member] \| Commercial Loans [Member]
With an allowance recorded [Abstract]
Recorded investment balance (book)	1,205		1,205		1,205
Unpaid principal balance (legal)	1,321		1,321		1,321
Related allowance	691		691		735
Acquired Loans [Member] \| Commercial Loans [Member] \| Commercial [Member]
With an allowance recorded [Abstract]
Average recorded investment	0	2,531	0	2,658
Interest income recognized	0	0	0	0
Acquired Loans [Member] \| Commercial Loans [Member] \| Commercial Real Estate [Member]
With an allowance recorded [Abstract]
Recorded investment balance (book)	1,205		1,205		1,205
Unpaid principal balance (legal)	1,321		1,321		1,321
Related allowance	691		691		$ 735
Average recorded investment	1,205	6,918	1,205	7,070
Interest income recognized	$ 0	$ 0	$ 0	$ 0

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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.

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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 15
-Subparagraph (c)(1)
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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