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Loans and ALLL (Summary of information pertaining to impaired loans) (Details) - USD ($) $ in Thousands | 3 Months Ended |
--- | --- | ---
Mar. 31, 2018 | Mar. 31, 2017 | Dec. 31, 2017
Impaired Financing Receivable, Recorded Investment [Abstract] |  |  |
Impaired loans with a valuation allowance, Outstanding Balance | $ 16,793 |  | $ 12,944
Impaired loans without a valuation allowance, Outstanding Balance | 14,302 |  | 13,709
Impaired loans, Outstanding Balance | 31,095 |  | 26,653
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |
Impaired loans with a valuation allowance, Unpaid Principal Balance | 17,709 |  | 13,876
Impaired loans without a valuation allowance, Unpaid Principal Balance | 14,676 |  | 14,083
Impaired loans, Unpaid Principal Balance | 32,385 |  | 27,959
Impaired loans, Valuation Allowance | 2,503 |  | 2,130
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |  |
Impaired loans with a valuation allowance, Average Outstanding Balance | 14,870 | $ 14,852 |
Impaired loans without a valuation allowance, Average Outstanding Balance | 14,007 | 7,078 |
Impaired loans, Average Outstanding Balance | 28,877 | 21,930 |
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |  |
Impaired loans with a valuation allowance, Interest Income Recognized | 193 | 180 |
Impaired loans without a valuation allowance, Interest Income Recognized | 133 | 115 |
Impaired loans, Interest Income Recognized | 326 | 295 |
Total commercial [Member] |  |  |
Impaired Financing Receivable, Recorded Investment [Abstract] |  |  |
Impaired loans, Outstanding Balance | 11,675 |  | 8,099
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |
Impaired loans, Unpaid Principal Balance | 12,037 |  | 8,462
Impaired loans, Valuation Allowance | 842 |  | 650
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |  |
Impaired loans, Average Outstanding Balance | 9,888 | 7,730 |
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |  |
Impaired loans, Interest Income Recognized | 167 | 132 |
Commercial real estate [Member] |  |  |
Impaired Financing Receivable, Recorded Investment [Abstract] |  |  |
Impaired loans with a valuation allowance, Outstanding Balance | 5,946 |  | 4,089
Impaired loans without a valuation allowance, Outstanding Balance | 2,466 |  | 1,791
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |
Impaired loans with a valuation allowance, Unpaid Principal Balance | 6,234 |  | 4,378
Impaired loans without a valuation allowance, Unpaid Principal Balance | 2,540 |  | 1,865
Impaired loans, Valuation Allowance | 639 |  | 626
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |  |
Impaired loans with a valuation allowance, Average Outstanding Balance | 5,018 | 5,015 |
Impaired loans without a valuation allowance, Average Outstanding Balance | 2,129 | 1,326 |
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |  |
Impaired loans with a valuation allowance, Interest Income Recognized | 91 | 73 |
Impaired loans without a valuation allowance, Interest Income Recognized | 35 | 33 |
Commercial other [Member] |  |  |
Impaired Financing Receivable, Recorded Investment [Abstract] |  |  |
Impaired loans with a valuation allowance, Outstanding Balance | 2,099 |  | 995
Impaired loans without a valuation allowance, Outstanding Balance | 1,164 |  | 1,224
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |
Impaired loans with a valuation allowance, Unpaid Principal Balance | 2,099 |  | 995
Impaired loans without a valuation allowance, Unpaid Principal Balance | 1,164 |  | 1,224
Impaired loans, Valuation Allowance | 203 |  | 24
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |  |
Impaired loans with a valuation allowance, Average Outstanding Balance | 1,547 | 1,275 |
Impaired loans without a valuation allowance, Average Outstanding Balance | 1,194 | 114 |
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |  |
Impaired loans with a valuation allowance, Interest Income Recognized | 24 | 24 |
Impaired loans without a valuation allowance, Interest Income Recognized | 17 | 2 |
Total agricultural [Member] |  |  |
Impaired Financing Receivable, Recorded Investment [Abstract] |  |  |
Impaired loans, Outstanding Balance | 11,468 |  | 10,598
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |
Impaired loans, Unpaid Principal Balance | 11,468 |  | 10,598
Impaired loans, Valuation Allowance | 141 |  | 0
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |  |
Impaired loans, Average Outstanding Balance | 11,034 | 5,547 |
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |  |
Impaired loans, Interest Income Recognized | 80 | 75 |
Agricultural real estate [Member] |  |  |
Impaired Financing Receivable, Recorded Investment [Abstract] |  |  |
Impaired loans with a valuation allowance, Outstanding Balance | 881 |  | 0
Impaired loans without a valuation allowance, Outstanding Balance | 8,082 |  | 7,913
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |
Impaired loans with a valuation allowance, Unpaid Principal Balance | 881 |  | 0
Impaired loans without a valuation allowance, Unpaid Principal Balance | 8,082 |  | 7,913
Impaired loans, Valuation Allowance | 141 |  | 0
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |  |
Impaired loans with a valuation allowance, Average Outstanding Balance | 441 | 0 |
Impaired loans without a valuation allowance, Average Outstanding Balance | 7,998 | 4,042 |
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |  |
Impaired loans with a valuation allowance, Interest Income Recognized | 4 | 0 |
Impaired loans without a valuation allowance, Interest Income Recognized | 40 | 62 |
Agricultural other [Member] |  |  |
Impaired Financing Receivable, Recorded Investment [Abstract] |  |  |
Impaired loans with a valuation allowance, Outstanding Balance | 0 |  | 0
Impaired loans without a valuation allowance, Outstanding Balance | 2,505 |  | 2,685
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |
Impaired loans with a valuation allowance, Unpaid Principal Balance | 0 |  | 0
Impaired loans without a valuation allowance, Unpaid Principal Balance | 2,505 |  | 2,685
Impaired loans, Valuation Allowance | 0 |  | 0
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |  |
Impaired loans with a valuation allowance, Average Outstanding Balance | 0 | 67 |
Impaired loans without a valuation allowance, Average Outstanding Balance | 2,595 | 1,438 |
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |  |
Impaired loans with a valuation allowance, Interest Income Recognized | 0 | 0 |
Impaired loans without a valuation allowance, Interest Income Recognized | 36 | 13 |
Total residential real estate [Member] |  |  |
Impaired Financing Receivable, Recorded Investment [Abstract] |  |  |
Impaired loans, Outstanding Balance | 7,940 |  | 7,939
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |
Impaired loans, Unpaid Principal Balance | 8,868 |  | 8,882
Impaired loans, Valuation Allowance | 1,520 |  | 1,480
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |  |
Impaired loans, Average Outstanding Balance | 7,940 | 8,628 |
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |  |
Impaired loans, Interest Income Recognized | 79 | 88 |
Residential real estate senior liens [Member] |  |  |
Impaired Financing Receivable, Recorded Investment [Abstract] |  |  |
Impaired loans with a valuation allowance, Outstanding Balance | 7,831 |  | 7,816
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |
Impaired loans with a valuation allowance, Unpaid Principal Balance | 8,459 |  | 8,459
Impaired loans, Valuation Allowance | 1,514 |  | 1,473
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |  |
Impaired loans with a valuation allowance, Average Outstanding Balance | 7,824 | 8,420 |
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |  |
Impaired loans with a valuation allowance, Interest Income Recognized | 74 | 83 |
Residential real estate junior liens [Member] |  |  |
Impaired Financing Receivable, Recorded Investment [Abstract] |  |  |
Impaired loans with a valuation allowance, Outstanding Balance | 36 |  | 44
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |
Impaired loans with a valuation allowance, Unpaid Principal Balance | 36 |  | 44
Impaired loans, Valuation Allowance | 6 |  | 7
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |  |
Impaired loans with a valuation allowance, Average Outstanding Balance | 40 | 75 |
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |  |
Impaired loans with a valuation allowance, Interest Income Recognized | 0 | 0 |
Residential real estate home equity lines of credit [Member] |  |  |
Impaired Financing Receivable, Recorded Investment [Abstract] |  |  |
Impaired loans without a valuation allowance, Outstanding Balance | 73 |  | 79
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |
Impaired loans without a valuation allowance, Unpaid Principal Balance | 373 |  | 379
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |  |
Impaired loans without a valuation allowance, Average Outstanding Balance | 76 | 133 |
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |  |
Impaired loans without a valuation allowance, Interest Income Recognized | 5 | 5 |
Total Consumer [Member] |  |  |
Impaired Financing Receivable, Recorded Investment [Abstract] |  |  |
Impaired loans, Outstanding Balance | 12 |  | 17
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |
Impaired loans, Unpaid Principal Balance | 12 |  | 17
Impaired loans, Valuation Allowance | 0 |  | 0
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |  |
Impaired loans, Average Outstanding Balance | 15 | 25 |
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |  |
Impaired loans, Interest Income Recognized | 0 | 0 |
Consumer secured [Member] |  |  |
Impaired Financing Receivable, Recorded Investment [Abstract] |  |  |
Impaired loans without a valuation allowance, Outstanding Balance | 12 |  | 17
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |  |
Impaired loans without a valuation allowance, Unpaid Principal Balance | 12 |  | $ 17
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |  |
Impaired loans without a valuation allowance, Average Outstanding Balance | 15 | 25 |
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |  |
Impaired loans without a valuation allowance, Interest Income Recognized | $ 0 | $ 0 |

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