Loans (Allowance for Loan Losses by Portfolio Class) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	$ 15,520	$ 15,312
Provision for Loan Losses	350	690
Recoveries	111	98
Loans Charged-off	(247)	(334)
Ending Balance	15,734	15,766
Commercial and Industrial Loans and Leases [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	4,555	3,493
Provision for Loan Losses	195	961
Recoveries	3	45
Loans Charged-off	0	(39)
Ending Balance	4,753	4,460
Commercial Real Estate Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	8,931	9,297
Provision for Loan Losses	6	58
Recoveries	51	19
Loans Charged-off	(109)	(140)
Ending Balance	8,879	9,234
Agricultural Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	989	926
Provision for Loan Losses	(223)	(175)
Recoveries	0	0
Loans Charged-off	0	0
Ending Balance	766	751
Home Equity Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	141	258
Provision for Loan Losses	41	(13)
Recoveries	0	1
Loans Charged-off	(64)	(42)
Ending Balance	118	204
Consumer Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	214	190
Provision for Loan Losses	(7)	46
Recoveries	55	31
Loans Charged-off	(73)	(71)
Ending Balance	189	196
Residential Mortgage Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	186	402
Provision for Loan Losses	113	79
Recoveries	2	2
Loans Charged-off	(1)	(42)
Ending Balance	300	441
Unallocated [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	504	746
Provision for Loan Losses	225	(266)
Recoveries	0	0
Loans Charged-off	0	0
Ending Balance	$ 729	$ 480