Loans, Impaired Financing Receivable (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	$ 17,510		$ 17,510		$ 19,050
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment With No Allowance	11,649		11,649		13,047
Recorded Investment With Allowance	3,683		3,683		4,230
Total Recorded Investment	15,332		15,332		17,277
Related Allowance	213		213		510
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	15,347	$ 16,997	16,194	$ 18,729
Interest Income Recognized	104	102	296	380
Interest Income Recognized Cash Basis	8	18	23	20
Real Estate Loans [Member] | Mortgages [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	757		757		1,070
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment With No Allowance	561		561		740
Recorded Investment With Allowance	46		46		123
Total Recorded Investment	607		607		863
Related Allowance	7		7		9
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	613	900	727	998
Interest Income Recognized	4	5	12	15
Interest Income Recognized Cash Basis	0	0	0	0
Real Estate Loans [Member] | Home Equity [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	100		100		150
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment With No Allowance	38		38		70
Recorded Investment With Allowance	45		45		57
Total Recorded Investment	83		83		127
Related Allowance	7		7		9
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	84	138	106	142
Interest Income Recognized	1	2	4	5
Interest Income Recognized Cash Basis	0	0	0	0
Real Estate Loans [Member] | Commercial [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	9,650		9,650		9,847
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment With No Allowance	7,937		7,937		8,323
Recorded Investment With Allowance	824		824		860
Total Recorded Investment	8,761		8,761		9,183
Related Allowance	85		85		95
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	8,688	9,436	8,902	10,836
Interest Income Recognized	77	75	211	294
Interest Income Recognized Cash Basis	8	18	23	20
Real Estate Loans [Member] | Agricultural [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	4,708		4,708		4,811
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment With No Allowance	2,734		2,734		2,799
Recorded Investment With Allowance	1,694		1,694		1,846
Total Recorded Investment	4,428		4,428		4,645
Related Allowance	17		17		83
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	4,454	3,633	4,513	3,718
Interest Income Recognized	21	18	64	58
Interest Income Recognized Cash Basis	0	0	0	0
Real Estate Loans [Member] | Construction [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance					0
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment With No Allowance					0
Recorded Investment With Allowance					0
Total Recorded Investment					0
Related Allowance					0
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	0	0
Interest Income Recognized	0	0
Interest Income Recognized Cash Basis	0	0
Consumer [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance					2
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment With No Allowance					2
Recorded Investment With Allowance					0
Total Recorded Investment					2
Related Allowance					0
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	0	5	1	3
Interest Income Recognized	0	0	0	0
Interest Income Recognized Cash Basis	0	0	0	0
Other Commercial Loans [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	1,088		1,088		1,908
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment With No Allowance	366		366		1,094
Recorded Investment With Allowance	96		96		241
Total Recorded Investment	462		462		1,335
Related Allowance	34		34		170
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	486	1,626	876	1,757
Interest Income Recognized	1	0	2	2
Interest Income Recognized Cash Basis	0	0	0	0
Other Agricultural Loans [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	1,207		1,207		1,262
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment With No Allowance	13		13		19
Recorded Investment With Allowance	978		978		1,103
Total Recorded Investment	991		991		1,122
Related Allowance	63		63		$ 144
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	1,022	1,259	1,069	1,275
Interest Income Recognized	0	2	3	6
Interest Income Recognized Cash Basis	0	0	0	$ 0
State and Political Subdivision Loans [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	0		0
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment With No Allowance	0		0
Recorded Investment With Allowance	0		0
Total Recorded Investment	0		0
Related Allowance	0		$ 0
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment	0	0
Interest Income Recognized	0	0
Interest Income Recognized Cash Basis	$ 0	$ 0