Loans (Aging of Past Due Loans) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 20,489		$ 19,974	[1]
Loans Not Past Due	3,071,509		3,075,928	[1]
Total	3,091,998		3,081,973
30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	5,219		11,879	[1]
60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	7,545		2,384	[1]
Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	7,725		5,711	[1]
Commercial and Industrial Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	3,827
Loans Not Past Due	634,946
Total	638,773	$ 534,692	589,758
Commercial and Industrial Loans | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	477
Commercial and Industrial Loans | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	909
Commercial and Industrial Loans | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	2,441
Commercial Real Estate Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	8,564		2,746
Loans Not Past Due	1,458,833		1,497,118
Total	1,467,397	1,500,247	1,495,862
Commercial Real Estate Loans | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	5		209
Commercial Real Estate Loans | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	4,877		431
Commercial Real Estate Loans | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	3,682		2,106
Agricultural Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	651		828
Loans Not Past Due	375,535		390,043
Total	376,186	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	0		0
Agricultural Loans | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	651		329
Leases
Financing Receivable, Past Due [Line Items]
Total Past Due	0
Loans Not Past Due	55,664
Total	55,664	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	948		1,454
Loans Not Past Due	218,400		225,321
Total	219,348	225,790	225,755
Home Equity Loans | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	672		1,121
Home Equity Loans | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	5		253
Home Equity Loans | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	271		80
Consumer Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	382		592
Loans Not Past Due	66,335		80,837
Total	66,717	69,264	81,217
Consumer Loans | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	233		347
Consumer Loans | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	84		156
Consumer Loans | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	65		89
Credit Cards
Financing Receivable, Past Due [Line Items]
Total Past Due	261
Loans Not Past Due	11,376
Total	11,637	11,953
Credit Cards | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	95
Credit Cards | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	80
Credit Cards | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	86
Residential Mortgage Loans
Financing Receivable, Past Due [Line Items]
Total Past Due	5,856		8,783
Loans Not Past Due	250,420		296,777
Total	256,276	$ 305,002	304,855
Residential Mortgage Loans | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	3,737		5,014
Residential Mortgage Loans | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	1,590		1,461
Residential Mortgage Loans | Greater Than 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 529		$ 2,308

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