Loans (Aging of Past Due Loans) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Jan. 01, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 18,106		$ 19,974	[1]
Loans Not Past Due	3,252,828		3,075,928	[1]
Total	3,270,934		3,081,973
Commercial and Industrial Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	5,535
Loans Not Past Due	790,153
Total	795,688	$ 534,692	589,758
Commercial Real Estate Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	1,332		2,746
Loans Not Past Due	1,471,902		1,497,118
Total	1,473,234	1,500,247	1,495,862
Agricultural Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	3,610		828
Loans Not Past Due	369,873		390,043
Total	373,483	384,654	384,526
Leases
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Loans Not Past Due	56,728
Total	56,728	57,257
Home Equity Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	884		1,454
Loans Not Past Due	215,482		225,321
Total	216,366	225,790	225,755
Consumer Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	710		592
Loans Not Past Due	64,262		80,837
Total	64,972	69,264	81,217
Credit Cards
Financing Receivable, Past Due [Line Items]
Total Past Due	295
Loans Not Past Due	9,922
Total	10,217	11,953
Residential Mortgage Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	5,740		8,783
Loans Not Past Due	274,506		296,777
Total	280,246	$ 305,002	304,855
30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	5,830		11,879	[1]
30-59 Days Past Due | Commercial and Industrial Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	238
30-59 Days Past Due | Commercial Real Estate Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	169		209
30-59 Days Past Due | Agricultural Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	927		499
30-59 Days Past Due | Leases
Financing Receivable, Past Due [Line Items]
Total Past Due	0
30-59 Days Past Due | Home Equity Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	539		1,121
30-59 Days Past Due | Consumer Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	608		347
30-59 Days Past Due | Credit Cards
Financing Receivable, Past Due [Line Items]
Total Past Due	70
30-59 Days Past Due | Residential Mortgage Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	3,279		5,014
60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	1,905		2,384	[1]
60-89 Days Past Due | Commercial and Industrial Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	171
60-89 Days Past Due | Commercial Real Estate Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	37		431
60-89 Days Past Due | Agricultural Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	89		0
60-89 Days Past Due | Leases
Financing Receivable, Past Due [Line Items]
Total Past Due	0
60-89 Days Past Due | Home Equity Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	87		253
60-89 Days Past Due | Consumer Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	11		156
60-89 Days Past Due | Credit Cards
Financing Receivable, Past Due [Line Items]
Total Past Due	34
60-89 Days Past Due | Residential Mortgage Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	1,476		1,461
Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	10,371		5,711	[1]
Greater Than 89 Days Past Due | Commercial and Industrial Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	5,126
Greater Than 89 Days Past Due | Commercial Real Estate Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	1,126		2,106
Greater Than 89 Days Past Due | Agricultural Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	2,594		329
Greater Than 89 Days Past Due | Leases
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Greater Than 89 Days Past Due | Home Equity Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	258		80
Greater Than 89 Days Past Due | Consumer Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	91		89
Greater Than 89 Days Past Due | Credit Cards
Financing Receivable, Past Due [Line Items]
Total Past Due	191
Greater Than 89 Days Past Due | Residential Mortgage Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 985		$ 2,308

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