Loans (Risk Category of Loans) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	$ 1,456,830	[1]	$ 1,457,768	[2]
Loans Acquired with Deteriorated Credit Quality	7,966		8,361
Commercial and Industrial Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	389,226	[1]	380,851	[2]
Loans Acquired with Deteriorated Credit Quality	396		354
Commercial Real Estate Loans
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	582,736	[1]	584,426	[2]
Loans Acquired with Deteriorated Credit Quality	6,070		6,385
Agricultural Loans
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	215,560	[1]	219,640	[2]
Loans Acquired with Deteriorated Credit Quality	0		0
Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	1,115,289		1,112,028
Loans Acquired with Deteriorated Credit Quality	660		651
Pass | Commercial and Industrial Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	360,305		351,250
Pass | Commercial Real Estate Loans
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	544,672		545,804
Pass | Agricultural Loans
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	210,312		214,974
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	45,442		46,019
Loans Acquired with Deteriorated Credit Quality	1,740		1,697
Special Mention | Commercial and Industrial Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	17,144		18,387
Special Mention | Commercial Real Estate Loans
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	23,505		23,421
Special Mention | Agricultural Loans
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	4,793		4,211
Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	26,791		26,870
Loans Acquired with Deteriorated Credit Quality	4,066		4,391
Substandard | Commercial and Industrial Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	11,777		11,214
Substandard | Commercial Real Estate Loans
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	14,559		15,201
Substandard | Agricultural Loans
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	455		455
Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	0		0
Loans Acquired with Deteriorated Credit Quality	0		0
Doubtful | Commercial and Industrial Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	0		0
Doubtful | Commercial Real Estate Loans
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	0		0
Doubtful | Agricultural Loans
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	0		0
Total
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	1,187,522		1,184,917
Loans Acquired with Deteriorated Credit Quality	6,466		6,739
Total | Commercial and Industrial Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	389,226		380,851
Total | Commercial Real Estate Loans
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	582,736		584,426
Total | Agricultural Loans
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	$ 215,560		$ 219,640

[1] Total recorded investment in loans includes $5,946 in accrued interest.

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