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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 | 6 Months Ended
--- | --- | ---
Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017
Average Recorded Investment and Interest Income Recognized [Abstract] |  |  |  |
Average recorded investment | $ 20,257 | $ 24,508 | $ 20,668 | $ 25,446
Interest income recognized | 214 | 194 | 436 | 422
Originated Loans [Member] |  |  |  |
Average Recorded Investment and Interest Income Recognized [Abstract] |  |  |  |
Average recorded investment | 20,257 | 24,508 | 20,668 | 25,274
Interest income recognized | 214 | 194 | 436 | 422
Originated Loans [Member] | Commercial Loans [Member] |  |  |  |
Average Recorded Investment and Interest Income Recognized [Abstract] |  |  |  |
Average recorded investment | 5,373 | 9,770 | 5,599 | 10,520
Interest income recognized | 36 | 15 | 73 | 72
Originated Loans [Member] | Commercial Loans [Member] | C&I [Member] |  |  |  |
Average Recorded Investment and Interest Income Recognized [Abstract] |  |  |  |
Average recorded investment | 447 |  | 457 |
Interest income recognized | 1 |  | 1 |
Originated Loans [Member] | Commercial Loans [Member] | CRE [Member] |  |  |  |
Average Recorded Investment and Interest Income Recognized [Abstract] |  |  |  |
Average recorded investment | 3,882 |  | 4,154 |
Interest income recognized | 32 |  | 64 |
Originated Loans [Member] | Commercial Loans [Member] | Commercial [Member] |  |  |  |
Average Recorded Investment and Interest Income Recognized [Abstract] |  |  |  |
Average recorded investment |  | 3,931 |  | 3,419
Interest income recognized |  | 0 |  | 0
Originated Loans [Member] | Commercial Loans [Member] | Commercial Real Estate [Member] |  |  |  |
Average Recorded Investment and Interest Income Recognized [Abstract] |  |  |  |
Average recorded investment |  | 3,243 |  | 4,584
Interest income recognized |  | 1 |  | 45
Originated Loans [Member] | Commercial Loans [Member] | Agricultural [Member] |  |  |  |
Average Recorded Investment and Interest Income Recognized [Abstract] |  |  |  |
Average recorded investment |  | 157 |  | 165
Interest income recognized |  | 1 |  | 1
Originated Loans [Member] | Commercial Loans [Member] | Agricultural Real Estate [Member] |  |  |  |
Average Recorded Investment and Interest Income Recognized [Abstract] |  |  |  |
Average recorded investment |  | 1,549 |  | 1,564
Interest income recognized |  | 10 |  | 21
Originated Loans [Member] | Commercial Loans [Member] | Business Banking [Member] |  |  |  |
Average Recorded Investment and Interest Income Recognized [Abstract] |  |  |  |
Average recorded investment | 1,044 | 890 | 988 | 788
Interest income recognized | 3 | 3 | 8 | 5
Originated Loans [Member] | Consumer Loans [Member] |  |  |  |
Average Recorded Investment and Interest Income Recognized [Abstract] |  |  |  |
Average recorded investment | 8,146 | 8,350 | 8,254 | 8,446
Interest income recognized | 107 | 111 | 219 | 221
Originated Loans [Member] | Consumer Loans [Member] | Dealer Finance [Member] |  |  |  |
Average Recorded Investment and Interest Income Recognized [Abstract] |  |  |  |
Average recorded investment | 194 |  | 188 |
Interest income recognized | 1 |  | 4 |
Originated Loans [Member] | Consumer Loans [Member] | Direct Lending [Member] |  |  |  |
Average Recorded Investment and Interest Income Recognized [Abstract] |  |  |  |
Average recorded investment | 7,952 |  | 8,066 |
Interest income recognized | 106 |  | 215 |
Originated Loans [Member] | Consumer Loans [Member] | Indirect [Member] |  |  |  |
Average Recorded Investment and Interest Income Recognized [Abstract] |  |  |  |
Average recorded investment |  | 25 |  | 16
Interest income recognized |  | 1 |  | 1
Originated Loans [Member] | Consumer Loans [Member] | Home Equity [Member] |  |  |  |
Average Recorded Investment and Interest Income Recognized [Abstract] |  |  |  |
Average recorded investment |  | 8,205 |  | 8,310
Interest income recognized |  | 110 |  | 220
Originated Loans [Member] | Consumer Loans [Member] | Direct [Member] |  |  |  |
Average Recorded Investment and Interest Income Recognized [Abstract] |  |  |  |
Average recorded investment |  | 120 |  | 120
Interest income recognized |  | 0 |  | 0
Originated Loans [Member] | Residential Real Estate [Member] |  |  |  |
Average Recorded Investment and Interest Income Recognized [Abstract] |  |  |  |
Average recorded investment | 6,738 | 6,388 | 6,815 | 6,308
Interest income recognized | $ 71 | $ 68 | 144 | 129
Acquired Loans [Member] |  |  |  |
Average Recorded Investment and Interest Income Recognized [Abstract] |  |  |  |
Average recorded investment |  |  | 0 | 172
Interest income recognized |  |  | 0 | 0
Acquired Loans [Member] | Commercial Loans [Member] |  |  |  |
Average Recorded Investment and Interest Income Recognized [Abstract] |  |  |  |
Average recorded investment |  |  | 0 | 172
Interest income recognized |  |  | 0 | 0
Acquired Loans [Member] | Commercial Loans [Member] | Commercial Real Estate [Member] |  |  |  |
Average Recorded Investment and Interest Income Recognized [Abstract] |  |  |  |
Average recorded investment |  |  | 0 | 172
Interest income recognized |  |  | $ 0 | $ 0

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