Allowance for Loan Losses and Credit Quality of Loans, Impaired Loans (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance for Loan Losses and Credit Quality of Loans [Abstract]
Minimum balance for classified loans to be evaluated individually for impairment	$ 500
With an allowance recorded [Abstract]
Recorded investment balance (book)	25,796	31,440
Unpaid principal balance (legal)	32,290	35,430
Related allowance	1,100	715
Average recorded investment	31,059	23,317	17,403
Interest income recognized accrual	772	418	643
Originated Loans [Member]
With no allowance recorded [Abstract]
Recorded investment balance (book)	17,358	16,360
Unpaid principal balance (legal)	19,181	18,173
Originated Loans [Member] \| Commercial Loans [Member]
With no allowance recorded [Abstract]
Recorded investment balance (book)	8,316	11,100
Unpaid principal balance (legal)	9,189	12,446
Originated Loans [Member] \| Commercial [Member]
With no allowance recorded [Abstract]
Recorded investment balance (book)	1,748	4,721
Unpaid principal balance (legal)	1,901	4,777
With an allowance recorded [Abstract]
Average recorded investment	1,954	3,488	6,682
Interest income recognized accrual	115	0	56
Originated Loans [Member] \| Commercial Real Estate [Member]
With no allowance recorded [Abstract]
Recorded investment balance (book)	4,505	4,613
Unpaid principal balance (legal)	4,520	5,164
With an allowance recorded [Abstract]
Recorded investment balance (book)	2,763	5,020
Unpaid principal balance (legal)	4,611	6,877
Related allowance	600	715
Average recorded investment	9,679	11,085	4,944
Interest income recognized accrual	169	95	230
Originated Loans [Member] \| Agricultural [Member]
With no allowance recorded [Abstract]
Recorded investment balance (book)	20	125
Unpaid principal balance (legal)	26	195
With an allowance recorded [Abstract]
Average recorded investment	91	1,035	1,767
Interest income recognized accrual	1	1	43
Originated Loans [Member] \| Agricultural Real Estate [Member]
With no allowance recorded [Abstract]
Recorded investment balance (book)	1,147	1,431
Unpaid principal balance (legal)	1,441	1,708
With an allowance recorded [Abstract]
Average recorded investment	1,346	1,067	922
Interest income recognized accrual	46	47	72
Originated Loans [Member] \| Business Banking [Member]
With no allowance recorded [Abstract]
Recorded investment balance (book)	896	210
Unpaid principal balance (legal)	1,301	602
With an allowance recorded [Abstract]
Average recorded investment	610	127	68
Interest income recognized accrual	55	61	65
Originated Loans [Member] \| Consumer Loans [Member]
With no allowance recorded [Abstract]
Recorded investment balance (book)	5,498	3,248
Unpaid principal balance (legal)	6,033	3,472
Originated Loans [Member] \| Home Equity [Member]
With an allowance recorded [Abstract]
Average recorded investment	5,198	3,120	1,877
Interest income recognized accrual	267	145	123
Originated Loans [Member] \| Residential Real Estate Mortgages [Member]
With no allowance recorded [Abstract]
Recorded investment balance (book)	3,544	2,012
Unpaid principal balance (legal)	3,959	2,255
With an allowance recorded [Abstract]
Average recorded investment	3,039	2,085	1,143
Interest income recognized accrual	119	69	54
Acquired Loans [Member] \| Commercial Loans [Member]
With no allowance recorded [Abstract]
Recorded investment balance (book)	2,666	10,060
Unpaid principal balance (legal)	3,830	10,380
Acquired Loans [Member] \| Commercial [Member]
With no allowance recorded [Abstract]
Recorded investment balance (book)	0	6,501
Unpaid principal balance (legal)	0	6,538
With an allowance recorded [Abstract]
Recorded investment balance (book)	3,009	0
Unpaid principal balance (legal)	4,668	0
Related allowance	500	0
Average recorded investment	5,756	0	0
Interest income recognized accrual	0	0	0
Acquired Loans [Member] \| Commercial Real Estate [Member]
With no allowance recorded [Abstract]
Recorded investment balance (book)	2,666	3,559
Unpaid principal balance (legal)	3,830	3,842
With an allowance recorded [Abstract]
Average recorded investment	3,386	1,310	0
Interest income recognized accrual	$ 0	$ 0	$ 0

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

+ 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://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=35738203&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=35738203&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.

+ References

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- Definition

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 14A

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953550-111524

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Amount of allowance for credit losses related to recorded investment.

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- Definition

Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses.

+ References

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Amount of investment in impaired financing receivables for which there is no related allowance for credit losses.

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- Definition

Amount of unpaid principal balance of impaired financing receivables for which there is no related allowance for credit losses.

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Amount of investment in impaired financing receivables for which there is a related allowance for credit losses.

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Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses.

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