Allowance for Loan Losses and Credit Quality of Loans, Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Allowance for Loan Losses and Credit Quality of Loans [Abstract]
Minimum balance for classified loans to be evaluated individually for impairment	$ 500		$ 500
With an allowance recorded [Abstract]
Recorded investment balance (book)	35,603		35,603		$ 27,168
Unpaid principal balance (legal)	39,749		39,749		31,665
Related allowance	3,215		3,215		2,005
Average recorded investment	35,641	$ 33,604	34,382	$ 33,363
Interest income recognized	204	241	484	425
Originated Loans [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	25,985		25,985		21,296
Unpaid principal balance (legal)	28,167		28,167		23,828
With an allowance recorded [Abstract]
Average recorded investment	34,436	23,797	33,177	23,465
Interest income recognized	204	241	484	425
Originated Loans [Member] \| Commercial Loans [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	11,621		11,621		7,586
Unpaid principal balance (legal)	12,133		12,133		8,606
With an allowance recorded [Abstract]
Recorded investment balance (book)	8,413		8,413		4,667
Unpaid principal balance (legal)	10,261		10,261		6,516
Related allowance	2,385		2,385		1,270
Originated Loans [Member] \| Commercial Loans [Member] \| Commercial [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	2,194		2,194		2,244
Unpaid principal balance (legal)	2,444		2,444		2,490
With an allowance recorded [Abstract]
Recorded investment balance (book)	1,022		1,022		457
Unpaid principal balance (legal)	1,022		1,022		457
Related allowance	495		495		300
Average recorded investment	3,126	1,768	2,972	1,742
Interest income recognized	0	61	0	86
Originated Loans [Member] \| Commercial Loans [Member] \| Commercial Real Estate [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	7,836		7,836		3,165
Unpaid principal balance (legal)	7,905		7,905		3,175
With an allowance recorded [Abstract]
Recorded investment balance (book)	7,391		7,391		4,210
Unpaid principal balance (legal)	9,239		9,239		6,059
Related allowance	1,890		1,890		970
Average recorded investment	15,278	9,060	14,264	9,091
Interest income recognized	0	41	74	82
Originated Loans [Member] \| Commercial Loans [Member] \| Agricultural [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	18		18		576
Unpaid principal balance (legal)	24		24		1,164
With an allowance recorded [Abstract]
Average recorded investment	18	19	98	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)	608		608		618
Unpaid principal balance (legal)	733		733		744
With an allowance recorded [Abstract]
Average recorded investment	610	630	613	633
Interest income recognized	11	12	22	23
Originated Loans [Member] \| Commercial Loans [Member] \| Business Banking [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	965		965		983
Unpaid principal balance (legal)	1,027		1,027		1,033
With an allowance recorded [Abstract]
Average recorded investment	969	975	973	932
Interest income recognized	6	2	12	6
Originated Loans [Member] \| Consumer Loans [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	8,190		8,190		7,693
Unpaid principal balance (legal)	9,141		9,141		8,595
Originated Loans [Member] \| Consumer Loans [Member] \| Indirect [Member]
With no related allowance recorded [Abstract]
Recorded investment balance (book)	8		8		12
Unpaid principal balance (legal)	19		19		21
With an allowance recorded [Abstract]
Average recorded investment	9	16	10	11
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)	8,182		8,182		7,681
Unpaid principal balance (legal)	9,121		9,121		8,574
With an allowance recorded [Abstract]
Average recorded investment	8,223	6,692	8,093	6,560
Interest income recognized	120	92	241	164
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)	1		1		0
With an allowance recorded [Abstract]
Average recorded investment	0	1	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)	6,174		6,174		6,017
Unpaid principal balance (legal)	6,893		6,893		6,627
With an allowance recorded [Abstract]
Average recorded investment	6,203	4,636	6,154	4,476
Interest income recognized	67	33	134	63
Acquired Loans [Member]
With an allowance recorded [Abstract]
Average recorded investment	1,205	9,807	1,205	9,898
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	830		830		735
Acquired Loans [Member] \| Commercial Loans [Member] \| Commercial [Member]
With an allowance recorded [Abstract]
Average recorded investment	0	2,602	0	2,722
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	830		830		$ 735
Average recorded investment	1,205	7,205	1,205	7,176
Interest income recognized	$ 0	$ 0	$ 0	$ 0

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

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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=49124121&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=49124121&loc=d3e5258-111524

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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
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-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953550-111524

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