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Recent Accounting Pronouncements (Impact of ASC 326 in Balance Sheet as January 1, 2020) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans	$ 3,120,981	$ 3,091,998			$ 3,081,973
Allowance for Credit Losses	(45,099)	(46,859)	$ (36,641)	$ (31,931)	(16,278)
Allowance for Credit Losses on Unfunded Loan Commitments				(173)
December 31, 2019 After Reclassification
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans					3,081,973
Allowance for Credit Losses					(16,278)
Allowance for Credit Losses on Unfunded Loan Commitments					0
Impact of ASC 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans					0
Allowance for Credit Losses				(15,653)
Allowance for Credit Losses on Unfunded Loan Commitments				(173)
Commercial and Industrial Loans
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans	672,300	638,773		534,692	589,758
Allowance for Credit Losses	(6,248)	(6,445)	(8,814)		(4,799)
Commercial and Industrial Loans \| December 31, 2019 After Reclassification
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans					532,501
Commercial and Industrial Loans \| Impact of ASC 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans				2,191	(57,257)
Commercial Real Estate Loans
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans	1,492,617	1,467,397		1,500,247	1,495,862
Allowance for Credit Losses	(28,540)	(29,878)	(17,310)		(4,692)
Commercial Real Estate Loans \| December 31, 2019 After Reclassification
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans					1,495,862
Commercial Real Estate Loans \| Impact of ASC 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans				4,385
Agricultural Loans
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans	347,231	376,186		384,654	384,526
Allowance for Credit Losses	(6,462)	(6,756)	(6,485)		(5,315)
Agricultural Loans \| December 31, 2019 After Reclassification
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans					384,526
Agricultural Loans \| Impact of ASC 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans				128
Leases
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans	55,714	55,664		57,257
Allowance for Credit Losses	(201)	(200)	(172)		0
Leases \| December 31, 2019 After Reclassification
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans					57,257
Leases \| Impact of ASC 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans				0	57,257
Home Equity Loans
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans	212,306	219,348		225,790	225,755
Allowance for Credit Losses	(965)	(996)	(977)		(200)
Home Equity Loans \| December 31, 2019 After Reclassification
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans					225,755
Home Equity Loans \| Impact of ASC 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans				35
Consumer Loans
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans	60,570	66,717		69,264	81,217
Allowance for Credit Losses	(439)	(490)	(455)		(434)
Consumer Loans \| December 31, 2019 After Reclassification
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans					69,264
Consumer Loans \| Impact of ASC 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans				0	(11,953)
Credit Cards
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans	12,609	11,637		11,953
Allowance for Credit Losses	(162)	(150)	(124)		0
Credit Cards \| December 31, 2019 After Reclassification
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans					11,953
Credit Cards \| Impact of ASC 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans				0	11,953
Residential Mortgage Loans
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans	267,634	256,276		305,002	304,855
Allowance for Credit Losses	$ (2,082)	$ (1,944)	$ (2,304)		(333)
Residential Mortgage Loans \| December 31, 2019 After Reclassification
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans					$ 304,855
Residential Mortgage Loans \| Impact of ASC 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans				$ 147