Loans (Schedule of Risk Category of Loans) (Details) - USD ($) $ in Thousands	Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	$ 3,095,902	[1]	$ 2,744,042	[2]
Commercial and Industrial Loans and Leases
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	591,403	[1]	545,342	[2]
Commercial Real Estate Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	1,499,864	[1]	1,211,882	[2]
Agricultural Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	390,871	[1]	370,694	[2]
Loans Acquired with Deteriorated Credit Quality
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	12,798		11,556		$ 9,117
Loans Acquired with Deteriorated Credit Quality | Loans Acquired in Current Year
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	321,464		481,901
Loans Acquired with Deteriorated Credit Quality | Commercial and Industrial Loans and Leases
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	1,368		1,038		988
Loans Acquired with Deteriorated Credit Quality | Commercial Real Estate Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	7,212		6,993		6,452
Loans Acquired with Deteriorated Credit Quality | Agricultural Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	3,161		1,877		$ 789
Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	2,336,007		1,996,743
Pass | Commercial and Industrial Loans and Leases
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	556,706		517,497
Pass | Commercial Real Estate Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	1,453,310		1,165,937
Pass | Agricultural Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	325,991		313,309
Pass | Loans Acquired with Deteriorated Credit Quality
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	68		0
Pass | Loans Acquired with Deteriorated Credit Quality | Loans Acquired in Current Year
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	254,629		250,415
Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	99,228		75,247
Special Mention | Commercial and Industrial Loans and Leases
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	19,671		7,541
Special Mention | Commercial Real Estate Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	30,504		26,723
Special Mention | Agricultural Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	49,053		40,983
Special Mention | Loans Acquired with Deteriorated Credit Quality
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	613		1,436
Special Mention | Loans Acquired with Deteriorated Credit Quality | Loans Acquired in Current Year
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	16,535		14,972
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	46,903		55,928
Substandard | Commercial and Industrial Loans and Leases
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	15,026		20,304
Substandard | Commercial Real Estate Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	16,050		19,222
Substandard | Agricultural Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	15,827		16,402
Substandard | Loans Acquired with Deteriorated Credit Quality
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	11,060		8,472
Substandard | Loans Acquired with Deteriorated Credit Quality | Loans Acquired in Current Year
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	12,769		11,521
Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	0		0
Doubtful | Commercial and Industrial Loans and Leases
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	0		0
Doubtful | Commercial Real Estate Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	0		0
Doubtful | Agricultural Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	0		0
Doubtful | Loans Acquired with Deteriorated Credit Quality
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	0		0
Doubtful | Loans Acquired with Deteriorated Credit Quality | Loans Acquired in Current Year
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	0		0
Total
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	2,482,138		2,127,918
Total | Commercial and Industrial Loans and Leases
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	591,403		545,342
Total | Commercial Real Estate Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	1,499,864		1,211,882
Total | Agricultural Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	390,871		370,694
Total | Loans Acquired with Deteriorated Credit Quality
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	11,741		9,908
Total | Loans Acquired with Deteriorated Credit Quality | Loans Acquired in Current Year
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of deferred income	$ 283,933		$ 276,908

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

[2] Total recorded investment in loans includes $12,301 in accrued interest.