Loans (Schedule of Carrying Amount of Loans with Deterioration of Credit Quality) (Details) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred income	[1]	$ 1,995,026	$ 2,001,415
Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred income		10,348	11,048
Carrying Amount, Net of Allowance		10,232	10,943
Commercial and Industrial Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred income	[1]	451,677	458,538
Commercial and Industrial Loans and Leases | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred income		1,251	1,656
Commercial Real Estate Loans
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred income	[1]	867,635	858,030
Commercial Real Estate Loans | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred income		7,426	7,688
Agricultural Loans
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred income	[1]	296,580	306,946
Agricultural Loans | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred income		688	706
Consumer Loans
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred income	[1]	59,088	60,099
Consumer Loans | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred income		53	53
Residential Mortgage Loans
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred income	[1]	184,218	183,770
Residential Mortgage Loans | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment [Line Items]
Loans, net of deferred income		$ 930	$ 945

[1] Total recorded investment in loans includes $8,097 in accrued interest.