Loans Receivable and Allowance for Loan Losses (Composition of the Loan Portfolio) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	$ 1,416,473		$ 924,676
Deferred fees, net	(1,811)		(95)
Total loans receivable	1,414,662		924,581
Allowance for loan losses	(11,674)	$ (10,312)	(8,509)	$ (8,405)	$ (8,228)	$ (8,452)
Net loans receivable	$ 1,402,988		$ 916,072
Percent of Loans	100.00%		100.00%
Residential Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	$ 263,404		$ 229,781
Allowance for loan losses	$ (1,678)	(1,652)	$ (1,552)	(1,568)	(1,447)	(1,328)
Percent of Loans	18.60%		24.90%
Commercial Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	$ 574,123		$ 391,327
Allowance for loan losses	$ (7,168)	(6,079)	$ (4,687)	(4,566)	(4,694)	(5,455)
Percent of Loans	40.50%		42.30%
Agricultural Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	$ 68,340
Percent of Loans	4.80%
Construction Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	$ 20,797		$ 17,732
Allowance for loan losses	$ (125)	(86)	$ (95)	(107)	(112)	(93)
Percent of Loans	1.50%		1.90%
Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	$ 285,295		$ 134,150
Allowance for loan losses	$ (1,209)	(1,076)	$ (949)	(943)	(896)	(712)
Percent of Loans	20.10%		14.50%
Other Agricultural Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	$ 42,297
Percent of Loans	3.00%
Consumer Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	$ 162,217		$ 151,686
Allowance for loan losses	$ (1,494)	$ (1,419)	$ (1,226)	$ (1,221)	$ (1,079)	$ (864)
Percent of Loans	11.50%		16.40%