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Loans and ALLL (Summary of recorded investment in loans by segments) (Details) - USD ($) $ in Thousands | Sep. 30, 2018 | Jun. 30, 2018 | Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Dec. 31, 2016
--- | --- | --- | --- | --- | --- | ---
Financing Receivable, Allowance for Credit Losses [Line Items] |  |  |  |  |  |
Individually evaluated for impairment, ALLL | $ 2,074 |  | $ 2,130 |  |  |
Collectively evaluated for impairment, ALLL | 6,026 |  | 5,570 |  |  |
Total, ALLL | 8,100 | $ 8,200 | 7,700 | $ 7,700 | $ 7,600 | $ 7,400
Individually evaluated for impairment, Loans | 31,354 |  | 26,653 |  |  |
Collectively evaluated for impairment, Loans | 1,108,576 |  | 1,064,866 |  |  |
Total | 1,139,930 |  | 1,091,519 |  |  |
Commercial [Member] |  |  |  |  |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |  |  |  |  |
Individually evaluated for impairment, ALLL | 481 |  | 650 |  |  |
Collectively evaluated for impairment, ALLL | 1,540 |  | 1,056 |  |  |
Total, ALLL | 2,021 | 2,197 | 1,706 | 2,169 | 1,978 | 1,814
Individually evaluated for impairment, Loans | 8,858 |  | 8,099 |  |  |
Collectively evaluated for impairment, Loans | 660,057 |  | 626,660 |  |  |
Total | 668,915 |  | 634,759 |  |  |
Agricultural [Member] |  |  |  |  |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |  |  |  |  |
Individually evaluated for impairment, ALLL | 193 |  | 0 |  |  |
Collectively evaluated for impairment, ALLL | 589 |  | 611 |  |  |
Total, ALLL | 782 | 982 | 611 | 435 | 475 | 884
Individually evaluated for impairment, Loans | 15,057 |  | 10,598 |  |  |
Collectively evaluated for impairment, Loans | 114,175 |  | 117,671 |  |  |
Total | 129,232 |  | 128,269 |  |  |
Residential Real Estate [Member] |  |  |  |  |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |  |  |  |  |
Individually evaluated for impairment, ALLL | 1,400 |  | 1,480 |  |  |
Collectively evaluated for impairment, ALLL | 982 |  | 1,083 |  |  |
Total, ALLL | 2,382 | 2,167 | 2,563 | 2,491 | 2,598 | 2,664
Individually evaluated for impairment, Loans | 7,429 |  | 7,939 |  |  |
Collectively evaluated for impairment, Loans | 269,475 |  | 264,429 |  |  |
Total | 276,904 |  | 272,368 |  |  |
Total Consumer [Member] |  |  |  |  |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |  |  |  |  |
Individually evaluated for impairment, ALLL | 0 |  | 0 |  |  |
Collectively evaluated for impairment, ALLL | 902 |  | 900 |  |  |
Total, ALLL | 902 | 882 | 900 | 633 | 583 | 624
Individually evaluated for impairment, Loans | 10 |  | 17 |  |  |
Collectively evaluated for impairment, Loans | 64,869 |  | 56,106 |  |  |
Total | 64,879 |  | 56,123 |  |  |
Unallocated [Member] |  |  |  |  |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |  |  |  |  |
Individually evaluated for impairment, ALLL | 0 |  | 0 |  |  |
Collectively evaluated for impairment, ALLL | 2,013 |  | 1,920 |  |  |
Total, ALLL | $ 2,013 | $ 1,972 | $ 1,920 | $ 1,972 | $ 1,966 | $ 1,414

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- Definition A valuation allowance for financing receivables that are expected to be uncollectible. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524 + Details
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