Loans (Schedule of Risk Category of Loans) (Details) - USD ($) $ in Thousands	Sep. 30, 2019		Dec. 31, 2018
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 3,074,146	[1]	$ 2,744,042	[2]
Loans Acquired With Deteriorated Credit Quality
Financing Receivable, Credit Quality Indicator [Line Items]
Total	14,300		11,556
Loans Acquired With Deteriorated Credit Quality | Loans Acquired in Current Year
Financing Receivable, Credit Quality Indicator [Line Items]
Total	338,803		481,901
Commercial and Industrial Loans and Leases
Financing Receivable, Credit Quality Indicator [Line Items]
Total	580,240	[1]	545,342	[2]
Commercial and Industrial Loans and Leases | Loans Acquired With Deteriorated Credit Quality
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,693		1,038
Commercial Real Estate Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,481,155	[1]	1,211,882	[2]
Commercial Real Estate Loans | Loans Acquired With Deteriorated Credit Quality
Financing Receivable, Credit Quality Indicator [Line Items]
Total	8,938		6,993
Agricultural Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	393,033	[1]	370,694	[2]
Agricultural Loans | Loans Acquired With Deteriorated Credit Quality
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,611		1,877
Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,308,283		1,996,743
Pass | Loans Acquired With Deteriorated Credit Quality
Financing Receivable, Credit Quality Indicator [Line Items]
Total	218		0
Pass | Loans Acquired With Deteriorated Credit Quality | Loans Acquired in Current Year
Financing Receivable, Credit Quality Indicator [Line Items]
Total	270,112		250,415
Pass | Commercial and Industrial Loans and Leases
Financing Receivable, Credit Quality Indicator [Line Items]
Total	547,949		517,497
Pass | Commercial Real Estate Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,432,250		1,165,937
Pass | Agricultural Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	328,084		313,309
Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total	95,703		75,247
Special Mention | Loans Acquired With Deteriorated Credit Quality
Financing Receivable, Credit Quality Indicator [Line Items]
Total	786		1,436
Special Mention | Loans Acquired With Deteriorated Credit Quality | Loans Acquired in Current Year
Financing Receivable, Credit Quality Indicator [Line Items]
Total	16,423		14,972
Special Mention | Commercial and Industrial Loans and Leases
Financing Receivable, Credit Quality Indicator [Line Items]
Total	15,990		7,541
Special Mention | Commercial Real Estate Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	31,533		26,723
Special Mention | Agricultural Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	48,180		40,983
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total	50,442		55,928
Substandard | Loans Acquired With Deteriorated Credit Quality
Financing Receivable, Credit Quality Indicator [Line Items]
Total	12,238		8,472
Substandard | Loans Acquired With Deteriorated Credit Quality | Loans Acquired in Current Year
Financing Receivable, Credit Quality Indicator [Line Items]
Total	13,185		11,521
Substandard | Commercial and Industrial Loans and Leases
Financing Receivable, Credit Quality Indicator [Line Items]
Total	16,301		20,304
Substandard | Commercial Real Estate Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	17,372		19,222
Substandard | Agricultural Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	16,769		16,402
Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0		0
Doubtful | Loans Acquired With Deteriorated Credit Quality
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0		0
Doubtful | Loans Acquired With Deteriorated Credit Quality | Loans Acquired in Current Year
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0		0
Doubtful | Commercial and Industrial Loans and Leases
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0		0
Doubtful | Commercial Real Estate Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0		0
Doubtful | Agricultural Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0		0
Total
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,454,428		2,127,918
Total | Loans Acquired With Deteriorated Credit Quality
Financing Receivable, Credit Quality Indicator [Line Items]
Total	13,242		9,908
Total | Loans Acquired With Deteriorated Credit Quality | Loans Acquired in Current Year
Financing Receivable, Credit Quality Indicator [Line Items]
Total	299,720		276,908
Total | Commercial and Industrial Loans and Leases
Financing Receivable, Credit Quality Indicator [Line Items]
Total	580,240		545,342
Total | Commercial Real Estate Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,481,155		1,211,882
Total | Agricultural Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 393,033		$ 370,694

[1] Total recorded investment in loans includes $13,404 in accrued interest.

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