Loans (Aging of Past Due Loans) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jan. 01, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 15,329		$ 19,974	[1]
Loans Not Past Due	3,209,903		3,075,928	[1]
Total	3,225,232		3,081,973
30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	5,760		11,879	[1]
60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	2,888		2,384	[1]
Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	6,681		5,711	[1]
Commercial and Industrial Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	4,683
Loans Not Past Due	776,864
Total	781,547	$ 534,692	589,758
Commercial and Industrial Loans | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	35
Commercial and Industrial Loans | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	160
Commercial and Industrial Loans | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	4,488
Commercial Real Estate Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	2,595		2,746
Loans Not Past Due	1,450,685		1,497,118
Total	1,453,280	1,500,247	1,495,862
Commercial Real Estate Loans | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	1,637		209
Commercial Real Estate Loans | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0		431
Commercial Real Estate Loans | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	958		2,106
Agricultural Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	651		828
Loans Not Past Due	375,564		390,043
Total	376,215	384,654	384,526
Agricultural Loans | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0		499
Agricultural Loans | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	578		0
Agricultural Loans | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	73		329
Leases
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Loans Not Past Due	57,475
Total	57,475	57,257
Leases | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Leases | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Leases | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Home Equity Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	714		1,454
Loans Not Past Due	217,926		225,321
Total	218,640	225,790	225,755
Home Equity Loans | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	401		1,121
Home Equity Loans | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	113		253
Home Equity Loans | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	200		80
Consumer Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	404		592
Loans Not Past Due	64,515		80,837
Total	64,919	69,264	81,217
Consumer Loans | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	259		347
Consumer Loans | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	61		156
Consumer Loans | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	84		89
Credit Cards
Financing Receivable, Past Due [Line Items]
Total Past Due	242
Loans Not Past Due	10,475
Total	10,717	11,953
Credit Cards | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	147
Credit Cards | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	29
Credit Cards | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	66
Residential Mortgage Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	6,040		8,783
Loans Not Past Due	256,399		296,777
Total	262,439	$ 305,002	304,855
Residential Mortgage Loans | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	3,281		5,014
Residential Mortgage Loans | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	1,947		1,461
Residential Mortgage Loans | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 812		$ 2,308

[1] Total recorded investment in loans includes $13,929 in accrued interest.