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Allowance for Loan Losses and Credit Quality of Loans, Average Recorded Investments on Loans Specifically Evaluated for Impairment and Interest Income Recognized (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2017 | Sep. 30, 2016 | Sep. 30, 2017 | Sep. 30, 2016
Financing Receivable, Impaired [Line Items] |  |  |  |
Average recorded investment | $ 20,936 | $ 36,521 | $ 23,789 | $ 35,116
Interest income recognized | 257 | 251 | 679 | 731
Originated Loans [Member] |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |
Average recorded investment | 20,936 | 35,316 | 23,668 | 33,911
Interest income recognized | 257 | 251 | 679 | 731
Originated Loans [Member] | Commercial Loans [Member] | Commercial [Member] |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |
Average recorded investment | 1,000 | 3,204 | 2,393 | 3,041
Interest income recognized | 0 | 0 | 0 | 0
Originated Loans [Member] | Commercial Loans [Member] | Commercial Real Estate [Member] |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |
Average recorded investment | 2,415 | 15,799 | 3,906 | 14,782
Interest income recognized | 48 | 48 | 93 | 122
Originated Loans [Member] | Commercial Loans [Member] | Agricultural [Member] |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |
Average recorded investment | 115 | 85 | 147 | 101
Interest income recognized | 0 | 0 | 1 | 1
Originated Loans [Member] | Commercial Loans [Member] | Agricultural Real Estate [Member] |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |
Average recorded investment | 1,505 | 935 | 1,545 | 742
Interest income recognized | 11 | 11 | 32 | 33
Originated Loans [Member] | Commercial Loans [Member] | Business Banking [Member] |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |
Average recorded investment | 955 | 743 | 837 | 882
Interest income recognized | 2 | 0 | 7 | 7
Originated Loans [Member] | Consumer Loans [Member] | Indirect [Member] |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |
Average recorded investment | 35 | 8 | 22 | 9
Interest income recognized | 1 | 0 | 2 | 0
Originated Loans [Member] | Consumer Loans [Member] | Home Equity [Member] |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |
Average recorded investment | 8,159 | 8,401 | 8,274 | 8,207
Interest income recognized | 111 | 116 | 331 | 357
Originated Loans [Member] | Consumer Loans [Member] | Direct [Member] |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |
Average recorded investment | 119 | 0 | 119 | 0
Interest income recognized | 2 | 0 | 2 | 0
Originated Loans [Member] | Residential Real Estate Mortgages [Member] |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |
Average recorded investment | 6,633 | 6,141 | 6,425 | 6,147
Interest income recognized | 82 | 76 | 211 | 211
Acquired Loans [Member] |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |
Average recorded investment | 0 | 1,205 | 121 | 1,205
Interest income recognized | 0 | 0 | 0 | 0
Acquired Loans [Member] | Commercial Loans [Member] | Commercial Real Estate [Member] |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |
Average recorded investment | 0 | 1,205 | 121 | 1,205
Interest income recognized | $ 0 | $ 0 | $ 0 | $ 0

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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=84173941&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=84173941&loc=d3e5258-111524 + Details
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