Loans (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	Jan. 01, 2021	Dec. 31, 2020
Summary of classes of loans (abstract)
Total Loans Receivable	$ 2,687,606,000	$ 2,680,124,000	$ 2,660,233,000
Net unamortized fees and costs	186,000		299,000
Total	2,687,792,000		2,660,532,000
Less allowance for credit losses and loan losses	35,850,000	36,620,000	35,470,000	$ 37,070,000	$ 37,070,000
Loans and receivable, net	2,651,942,000		2,625,062,000
Loans and Leases Receivable, Allowance	35,850,000		35,470,000
financing receivable, allowance for credit loss, change due to economic factors	540,000
Financing Receivable, Allowance for Credit Losses, change due to loan volume	420,000
Financing Receivable, Allowance for Credit Losses, change in prepayment and curtailment rates	240,000
Financing Receivable, Allowance for Credit Losses, change due to historical loss rates	180,000
Impact of ASC 326 Adoption
Summary of classes of loans (abstract)
Less allowance for credit losses and loan losses				$ 2,746,000	2,746,000
Agricultural [Member]
Summary of classes of loans (abstract)
Total Loans Receivable	104,900,000	96,042,000	106,933,000
Total	104,900,000		106,933,000
Less allowance for credit losses and loan losses	2,414,000	2,147,000	2,261,000		2,508,000
Agricultural [Member] | Impact of ASC 326 Adoption
Summary of classes of loans (abstract)
Less allowance for credit losses and loan losses					(328,000)
Commercial and Financial [Member]
Summary of classes of loans (abstract)
Total Loans Receivable	223,702,000	281,337,000	222,002,000
Total	223,702,000		222,002,000
Less allowance for credit losses and loan losses	4,895,000	5,114,000	4,269,000		4,885,000
Commercial and Financial [Member] | Impact of ASC 326 Adoption
Summary of classes of loans (abstract)
Less allowance for credit losses and loan losses					298,000
Commercial and Financial [Member] | Small Business Administration SBA, CARES Act, Paycheck Protection Program
Summary of classes of loans (abstract)
Loans and Leases Receivable, Before Unamortized Fees and Costs	910,000		5,340,000
Interest and fee income, Loans and Leases, PPP Loan fees recognized in income	0	1,880,000
Real Estate Construction One to Four Family Residential [Member]
Summary of classes of loans (abstract)
Total Loans Receivable	87,390,000		80,486,000
Total	87,390,000		80,486,000
Real Estate: Construction, land development and commercial [Member]
Summary of classes of loans (abstract)
Total Loans Receivable	135,353,000		127,021,000
Total	135,353,000		127,021,000
Real Estate: Mortgage, farmland [Member]
Summary of classes of loans (abstract)
Total Loans Receivable	236,573,000	246,665,000	232,744,000
Total	236,573,000		232,744,000
Less allowance for credit losses and loan losses	3,310,000	$ 4,668,000	3,433,000		4,173,000
Real Estate: Mortgage, farmland [Member] | Impact of ASC 326 Adoption
Summary of classes of loans (abstract)
Less allowance for credit losses and loan losses					$ 763,000
Real Estate: Mortgage, 1 to 4 family first liens [Member]
Summary of classes of loans (abstract)
Total Loans Receivable	919,734,000		909,564,000
Total	111,278,000		909,564,000
Real Estate: Mortgage, 1 to 4 family junior liens [Member]
Summary of classes of loans (abstract)
Total Loans Receivable	111,278,000		114,342,000
Total	919,734,000		114,342,000
Real Estate: Mortgage, multi-family [Member]
Summary of classes of loans (abstract)
Total Loans Receivable	381,942,000		382,792,000
Total	381,942,000		382,792,000
Real Estate: Mortgage, commercial [Member]
Summary of classes of loans (abstract)
Total Loans Receivable	404,769,000		401,377,000
Total	404,769,000		401,377,000
Loans to individuals [Member]
Summary of classes of loans (abstract)
Total Loans Receivable	31,568,000		32,687,000
Total	31,568,000		32,687,000
Obligations of state and political subdivisions [Member]
Summary of classes of loans (abstract)
Total Loans Receivable	50,397,000		50,285,000
Total	$ 50,397,000		$ 50,285,000