Loans, Allowance for Loan Losses by Portfolio Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	$ 15,815	$ 13,845
Charge-offs	(4)	(9)
Recoveries	99	11
Provision	650	400
Balance at end of period	16,560	14,247
Real Estate Loans [Member] | Residential [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	1,174	1,114
Charge-offs	0	0
Recoveries	0	0
Provision	(7)	40
Balance at end of period	1,167	1,154
Real Estate Loans [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	6,216	4,549
Charge-offs	0	(1)
Recoveries	89	1
Provision	378	180
Balance at end of period	6,683	4,729
Real Estate Loans [Member] | Agricultural [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	4,953	5,022
Charge-offs	0	0
Recoveries	0	0
Provision	(36)	(144)
Balance at end of period	4,917	4,878
Real Estate Loans [Member] | Construction [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	122	43
Charge-offs	0	0
Recoveries	0	0
Provision	29	13
Balance at end of period	151	56
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	321	112
Charge-offs	(4)	(8)
Recoveries	6	8
Provision	(86)	5
Balance at end of period	237	117
Other Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	1,226	1,255
Charge-offs	0	0
Recoveries	4	2
Provision	274	40
Balance at end of period	1,504	1,297
Other Agricultural Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	864	961
Charge-offs	0	0
Recoveries	0	0
Provision	(75)	(126)
Balance at end of period	789	835
State and Political Subdivision Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	479	536
Charge-offs	0	0
Recoveries	0	0
Provision	(9)	22
Balance at end of period	470	558
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	460	253
Charge-offs	0	0
Recoveries	0	0
Provision	182	370
Balance at end of period	$ 642	$ 623