Recent Accounting Pronouncements (Impact of ASC 326 in Loan Portfolio Segments as January 1, 2020) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans	$ 3,018,416		$ 3,081,973
Adjusted Balance
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans			3,081,973
Commercial and Industrial Loans
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans	509,947	$ 534,692	589,758
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 and Industrial Loans | Adjusted Balance
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans			532,501
Commercial Real Estate Loans
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans	1,489,353	1,500,247	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
Commercial Real Estate Loans | Adjusted Balance
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans			1,495,862
Agricultural Loans
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans	366,286	384,654	384,526
Agricultural Loans | Impact of ASC 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans		128
Agricultural Loans | Adjusted Balance
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans			384,526
Leases
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans	55,833	57,257
Leases | Impact of ASC 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans			57,257
Leases | Adjusted Balance
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans			57,257
Home Equity Loans
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans	224,306	225,790	225,755
Home Equity Loans | Impact of ASC 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans		35
Home Equity Loans | Adjusted Balance
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans			225,755
Consumer Loans
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans	68,085	69,264	81,217
Consumer Loans | Impact of ASC 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans			(11,953)
Consumer Loans | Adjusted Balance
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans			69,264
Credit Cards
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans	11,056	11,953
Credit Cards | Impact of ASC 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans			11,953
Credit Cards | Adjusted Balance
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans			11,953
Residential Mortgage Loans
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans	$ 293,550	305,002	304,855
Residential Mortgage Loans | Impact of ASC 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans		$ 147
Residential Mortgage Loans | Adjusted Balance
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans			$ 304,855