Loans Receivable and Allowance for Credit Losses (Composition of the Loan Portfolio) (Details) - USD ($)	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 1,621,680,000	$ 1,603,877,000
Deferred fees, net	(232,000)	(259,000)
Total loans receivable	1,621,448,000	1,603,618,000
Allowance for credit losses	(18,020,000)	(18,968,000)	$ (19,445,000)
Net loans receivable	$ 1,603,428,000	$ 1,584,650,000
Percent of Loans	100.00%	100.00%
Residential Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 313,531,000	$ 316,546,000
Allowance for credit losses	$ (1,197,000)	$ (1,351,000)	(1,359,000)
Percent of Loans	19.30%	19.70%
Commercial Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 691,755,000	$ 675,156,000
Allowance for credit losses	$ (9,831,000)	$ (11,871,000)	(13,725,000)
Percent of Loans	42.70%	42.10%
Agricultural Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 62,309,000	$ 63,859,000
Percent of Loans	3.90%	4.00%
Construction Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 47,409,000	$ 51,453,000
Allowance for credit losses	$ (831,000)	$ (933,000)	(703,000)
Percent of Loans	2.90%	3.20%
Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 204,006,000	$ 200,576,000
Allowance for credit losses	$ (1,987,000)	$ (1,207,000)	(1,158,000)
Percent of Loans	12.60%	12.50%
Other Agricultural Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 31,439,000	$ 31,966,000
Percent of Loans	1.90%	2.00%
Consumer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 271,231,000	$ 264,321,000
Allowance for credit losses	$ (3,922,000)	$ (3,454,000)	$ (2,297,000)
Percent of Loans	16.70%	16.50%