Loans (Schedule of Allowance for Loan Losses) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	$ 15,694	$ 14,808
Provision for Loan Losses	350	500
Recoveries	100	94
Loans Charged-off	(1,684)	(236)
Ending Balance	14,460	15,166
Commercial and Industrial Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	4,735	3,725
Provision for Loan Losses	367	(115)
Recoveries	1	2
Loans Charged-off	(1,500)	0
Ending Balance	3,603	3,612
Commercial Real Estate Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	4,591	5,452
Provision for Loan Losses	25	278
Recoveries	6	5
Loans Charged-off	0	(39)
Ending Balance	4,622	5,696
Agricultural Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	4,894	4,094
Provision for Loan Losses	(69)	267
Recoveries	0	0
Loans Charged-off	0	0
Ending Balance	4,825	4,361
Home Equity Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	330	283
Provision for Loan Losses	(44)	17
Recoveries	2	0
Loans Charged-off	(16)	(1)
Ending Balance	272	299
Consumer Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	298	235
Provision for Loan Losses	97	118
Recoveries	89	60
Loans Charged-off	(168)	(169)
Ending Balance	316	244
Residential Mortgage Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	343	329
Provision for Loan Losses	(18)	19
Recoveries	2	27
Loans Charged-off	0	(27)
Ending Balance	327	348
Unallocated
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	503	690
Provision for Loan Losses	(8)	(84)
Recoveries	0	0
Loans Charged-off	0	0
Ending Balance	$ 495	$ 606

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount, after recoveries, of loans and leases that have been written-off.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
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Amount of expense related to estimated loss from loan and lease transactions.

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