Loans and ALLL (Summary of recorded investment in loans by segments) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment, ALLL	$ 1,509	$ 1,938
Collectively evaluated for impairment, ALLL	6,889	6,437
Total, ALLL	8,398	8,375	$ 8,200	$ 7,700
Individually evaluated for impairment, Loans	30,033	31,099
Collectively evaluated for impairment, Loans	1,114,799	1,097,608
Total	1,144,832	1,128,707
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment, ALLL	94	443
Collectively evaluated for impairment, ALLL	2,154	2,120
Total, ALLL	2,248	2,563	1,840	1,706
Individually evaluated for impairment, Loans	9,456	9,899
Collectively evaluated for impairment, Loans	668,098	649,630
Total	677,554	659,529
Agricultural [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment, ALLL	118	132
Collectively evaluated for impairment, ALLL	657	643
Total, ALLL	775	775	1,224	611
Individually evaluated for impairment, Loans	13,989	14,298
Collectively evaluated for impairment, Loans	109,404	112,863
Total	123,393	127,161
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment, ALLL	1,297	1,363
Collectively evaluated for impairment, ALLL	1,008	629
Total, ALLL	2,305	1,992	2,482	2,563
Individually evaluated for impairment, Loans	6,580	6,893
Collectively evaluated for impairment, Loans	270,196	268,450
Total	276,776	275,343
Total Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment, ALLL	0	0
Collectively evaluated for impairment, ALLL	891	857
Total, ALLL	891	857	795	900
Individually evaluated for impairment, Loans	8	9
Collectively evaluated for impairment, Loans	67,101	66,665
Total	67,109	66,674
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment, ALLL	0	0
Collectively evaluated for impairment, ALLL	2,179	2,188
Total, ALLL	$ 2,179	$ 2,188	$ 1,859	$ 1,920

A valuation allowance for financing receivables that are expected to be uncollectible.

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-Topic 310
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