Loans (Risk Category of Loans) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	$ 1,372,489	[1]	$ 1,390,802	[2]
Loans Acquired with Deteriorated Credit Quality	13,869		14,753
Commercial and Industrial Loans and Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	344,872	[1]	351,903	[2]
Loans Acquired with Deteriorated Credit Quality	1,636		1,981
Commercial Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	590,668	[1]	583,604	[2]
Loans Acquired with Deteriorated Credit Quality	10,337		10,871
Agricultural Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	176,860	[1]	195,171	[2]
Loans Acquired with Deteriorated Credit Quality	0		0
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	1,032,247		1,056,827
Loans Acquired with Deteriorated Credit Quality	3,085		3,121
Pass [Member] | Commercial and Industrial Loans and Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	310,939		324,685
Pass [Member] | Commercial Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	548,452		539,533
Pass [Member] | Agricultural Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	172,856		192,609
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	43,005		38,010
Loans Acquired with Deteriorated Credit Quality	659		661
Special Mention [Member] | Commercial and Industrial Loans and Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	18,311		15,485
Special Mention [Member] | Commercial Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	20,895		20,168
Special Mention [Member] | Agricultural Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	3,799		2,357
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	37,148		35,841
Loans Acquired with Deteriorated Credit Quality	8,229		9,070
Substandard [Member] | Commercial and Industrial Loans and Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	15,622		11,733
Substandard [Member] | Commercial Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	21,321		23,903
Substandard [Member] | Agricultural Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	205		205
Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	0		0
Loans Acquired with Deteriorated Credit Quality	0		0
Doubtful [Member] | Commercial and Industrial Loans and Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	0		0
Doubtful [Member] | Commercial Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	0		0
Doubtful [Member] | Agricultural Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	0		0
Total by Risk Category [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	1,112,400		1,130,678
Loans Acquired with Deteriorated Credit Quality	11,973		12,852
Total by Risk Category [Member] | Commercial and Industrial Loans and Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	344,872		351,903
Total by Risk Category [Member] | Commercial Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	590,668		583,604
Total by Risk Category [Member] | Agricultural Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	$ 176,860		$ 195,171

[1] Total recorded investment in loans includes $5,305 in accrued interest.

[2] Total recorded investment in loans includes $5,590 in accrued interest.