Loans (Collateral-dependent Loans by Class) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jan. 01, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	$ 3,225,232		$ 3,081,973
Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	22,575
Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	3,383
Accounts Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	699
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	1,651
Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	28,308
Commercial and Industrial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	781,547	$ 534,692	589,758
Commercial and Industrial Loans | Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	4,973
Commercial and Industrial Loans | Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	3,380
Commercial and Industrial Loans | Accounts Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	699
Commercial and Industrial Loans | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	41
Commercial and Industrial Loans | Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	9,093
Commercial Real Estate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	1,453,280	1,500,247	1,495,862
Commercial Real Estate Loans | Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	13,036
Commercial Real Estate Loans | Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0
Commercial Real Estate Loans | Accounts Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0
Commercial Real Estate Loans | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	1,604
Commercial Real Estate Loans | Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	14,640
Agricultural Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	376,215	384,654	384,526
Agricultural Loans | Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	3,069
Agricultural Loans | Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0
Agricultural Loans | Accounts Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0
Agricultural Loans | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	1
Agricultural Loans | Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	3,070
Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	57,475	57,257
Leases | Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0
Leases | Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0
Leases | Accounts Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0
Leases | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0
Leases | Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0
Home Equity Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	218,640	225,790	225,755
Home Equity Loans | Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	415
Home Equity Loans | Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0
Home Equity Loans | Accounts Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0
Home Equity Loans | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0
Home Equity Loans | Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	415
Consumer Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	64,919	69,264	81,217
Consumer Loans | Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	39
Consumer Loans | Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	3
Consumer Loans | Accounts Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0
Consumer Loans | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	5
Consumer Loans | Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	47
Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	10,717	11,953
Credit Cards | Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0
Credit Cards | Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0
Credit Cards | Accounts Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0
Credit Cards | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0
Credit Cards | Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0
Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	262,439	$ 305,002	$ 304,855
Residential Mortgage Loans | Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	1,043
Residential Mortgage Loans | Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0
Residential Mortgage Loans | Accounts Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0
Residential Mortgage Loans | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0
Residential Mortgage Loans | Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	$ 1,043