Loans, Loans Portfolio by Credit Quality Indicators (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	$ 856,657	$ 849,060
Commercial and industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	37,155	36,103
Commercial, secured by real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	542,524	527,596
Residential real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	246,955	252,049
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	17,286	17,563
Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	12,231	15,210
Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	506	539
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	834,439	824,849
Pass [Member] | Commercial and industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	36,716	35,683
Pass [Member] | Commercial, secured by real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	523,298	506,833
Pass [Member] | Residential real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	244,998	250,039
Pass [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	17,252	17,522
Pass [Member] | Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	11,669	14,233
Pass [Member] | Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	506	539
OAEM [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	951	2,356
OAEM [Member] | Commercial and industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	155	176
OAEM [Member] | Commercial, secured by real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	796	2,180
OAEM [Member] | Residential real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	0	0
OAEM [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	0	0
OAEM [Member] | Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	0	0
OAEM [Member] | Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	0	0
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	21,267	21,855
Substandard [Member] | Commercial and industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	284	244
Substandard [Member] | Commercial, secured by real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	18,430	18,583
Substandard [Member] | Residential real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	1,957	2,010
Substandard [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	34	41
Substandard [Member] | Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	562	977
Substandard [Member] | Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	0	0
Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	0	0
Doubtful [Member] | Commercial and industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	0	0
Doubtful [Member] | Commercial, secured by real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	0	0
Doubtful [Member] | Residential real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	0	0
Doubtful [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	0	0
Doubtful [Member] | Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	0	0
Doubtful [Member] | Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred origination costs (fees)	$ 0	$ 0