Loans (Components of Loans) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Mar. 31, 2020	Jan. 01, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	$ 3,270,934			$ 3,081,973
Less: Unearned Income	(4,587)			(4,882)
Allowance for credit losses	(42,431)	$ (36,641)	$ (31,931)	(16,278)	$ (16,239)	$ (16,243)	$ (15,823)
Loans, Net	3,223,916			3,060,813
Commercial and Industrial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	795,688		534,692	589,758
Allowance for credit losses	(8,787)	(8,814)		(4,799)
Commercial Real Estate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	1,473,234		1,500,247	1,495,862
Allowance for credit losses	(22,369)	(17,310)		(4,692)	(5,841)	(5,741)	(5,291)
Agricultural Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	373,483		384,654	384,526
Allowance for credit losses	(7,030)	(6,485)		(5,315)	(5,725)	(5,453)	(5,776)
Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	56,728		57,257
Allowance for credit losses	(202)	(172)		0
Home Equity Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	216,366		225,790	225,755
Allowance for credit losses	(1,062)	(977)		(200)	(258)	(214)	(229)
Consumer Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	64,972		69,264	81,217
Allowance for credit losses	(496)	(455)		(434)	(422)	(483)	(420)
Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	10,217		11,953
Allowance for credit losses	(125)	(124)		0
Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	280,246		$ 305,002	304,855
Allowance for credit losses	(2,360)	$ (2,304)		(333)	$ (349)	$ (429)	$ (472)
Commercial | Commercial and Industrial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	795,688			532,501
Commercial | Commercial Real Estate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	1,473,234			1,495,862
Commercial | Agricultural Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	373,483			384,526
Commercial | Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	56,728			57,257
Retail | Home Equity Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	216,366			225,755
Retail | Consumer Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	64,972			69,264
Retail | Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	10,217			11,953
Retail | Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	$ 280,246			$ 304,855