Loans (Schedule of Risk Category of Loans) (Details) - USD ($) $ in Thousands	Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	$ 1,574,027	[1],[2]	$ 1,457,768	[3],[4]
Commercial and Industrial Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	419,176	[1]	380,851	[3]
Commercial Real Estate Loans
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	620,163	[1]	584,426	[3]
Agricultural Loans
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	249,699	[1]	219,640	[3]
Pass | Commercial and Industrial Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	393,270		351,250
Pass | Commercial Real Estate Loans
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	586,247		545,804
Pass | Agricultural Loans
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	242,728		214,974
Pass | Total
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	1,222,245		1,112,028
Special Mention | Commercial and Industrial Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	13,675		18,387
Special Mention | Commercial Real Estate Loans
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	25,341		23,421
Special Mention | Agricultural Loans
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	5,177		4,211
Special Mention | Total
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	44,193		46,019
Substandard | Commercial and Industrial Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	12,231		11,214
Substandard | Commercial Real Estate Loans
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	8,575		15,201
Substandard | Agricultural Loans
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	1,794		455
Substandard | Total
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	22,600		26,870
Doubtful | Commercial and Industrial Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	0		0
Doubtful | Commercial Real Estate Loans
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	0		0
Doubtful | Agricultural Loans
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	0		0
Doubtful | Total
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	0		0
Total by Risk Category | Commercial and Industrial Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	419,176		380,851
Total by Risk Category | Commercial Real Estate Loans
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	620,163		584,426
Total by Risk Category | Agricultural Loans
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	249,699		219,640
Total by Risk Category | Total
Financing Receivable, Recorded Investment [Line Items]
Total Ending Loans Balance	1,289,038		1,184,917
Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment [Line Items]
Loans Acquired with Deteriorated Credit Quality (Included in the Total Above)	7,555		8,361		$ 14,753
Receivables Acquired with Deteriorated Credit Quality | Commercial and Industrial Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Loans Acquired with Deteriorated Credit Quality (Included in the Total Above)	1,325		354		1,981
Receivables Acquired with Deteriorated Credit Quality | Commercial Real Estate Loans
Financing Receivable, Recorded Investment [Line Items]
Loans Acquired with Deteriorated Credit Quality (Included in the Total Above)	5,363		6,385		$ 10,871
Receivables Acquired with Deteriorated Credit Quality | Agricultural Loans
Financing Receivable, Recorded Investment [Line Items]
Loans Acquired with Deteriorated Credit Quality (Included in the Total Above)	0		0
Receivables Acquired with Deteriorated Credit Quality | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans Acquired with Deteriorated Credit Quality (Included in the Total Above)	1,572		651
Receivables Acquired with Deteriorated Credit Quality | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans Acquired with Deteriorated Credit Quality (Included in the Total Above)	3,319		1,697
Receivables Acquired with Deteriorated Credit Quality | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans Acquired with Deteriorated Credit Quality (Included in the Total Above)	1,797		4,391
Receivables Acquired with Deteriorated Credit Quality | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans Acquired with Deteriorated Credit Quality (Included in the Total Above)	0		0
Receivables Acquired with Deteriorated Credit Quality | Total by Risk Category
Financing Receivable, Recorded Investment [Line Items]
Loans Acquired with Deteriorated Credit Quality (Included in the Total Above)	$ 6,688		$ 6,739

[1] Total recorded investment in loans includes $5,952 in accrued interest.

[2] Total recorded investment in loans includes $5,952 in accrued interest.

[3] Total recorded investment in loans includes $5,778 in accrued interest.

[4] Total recorded investment in loans includes $5,778 in accrued interest.