Loans (Aging of Recorded Investment in Past Due Loans by Class of Loans) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Ending Loans Balance	$ 1,372,489	[1]	$ 1,390,802	[2]
30-59 Days Past Due	2,788	[1]	3,589	[2]
60-89 Days Past Due	668	[1]	431	[2]
90 Days or More Past Due	3,146	[1]	3,565	[2]
Total Past Due	6,602	[1]	7,585	[2]
Loans Not Past Due	1,365,887	[1]	1,383,217	[2]
Commercial and Industrial Loans and Leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Ending Loans Balance	344,872	[1]	351,903	[2]
30-59 Days Past Due	93		256
60-89 Days Past Due	111		78
90 Days or More Past Due	64		0
Total Past Due	268		334
Loans Not Past Due	344,604		351,569
Commercial Real Estate Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Ending Loans Balance	590,668	[1]	583,604	[2]
30-59 Days Past Due	619		613
60-89 Days Past Due	347		62
90 Days or More Past Due	1,331		2,234
Total Past Due	2,297		2,909
Loans Not Past Due	588,371		580,695
Agricultural Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Ending Loans Balance	176,860	[1]	195,171	[2]
30-59 Days Past Due	73		62
60-89 Days Past Due	5		0
90 Days or More Past Due	0		0
Total Past Due	78		62
Loans Not Past Due	176,782		195,109
Home Equity Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Ending Loans Balance	81,527	[1]	81,812	[2]
30-59 Days Past Due	269		303
60-89 Days Past Due	132		33
90 Days or More Past Due	138		114
Total Past Due	539		450
Loans Not Past Due	80,988		81,362
Consumer Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Ending Loans Balance	46,928	[1]	49,265	[2]
30-59 Days Past Due	103		149
60-89 Days Past Due	36		66
90 Days or More Past Due	190		102
Total Past Due	329		317
Loans Not Past Due	46,599		48,948
Residential Mortgage Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Ending Loans Balance	131,634	[1]	129,047	[2]
30-59 Days Past Due	1,631		2,206
60-89 Days Past Due	37		192
90 Days or More Past Due	1,423		1,115
Total Past Due	3,091		3,513
Loans Not Past Due	128,543		125,534
Loans Acquired With Deteriorated Credit Quality [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Ending Loans Balance	13,869		14,753
30-59 Days Past Due	0		148
60-89 Days Past Due	0		0
90 Days or More Past Due	996		1,103
Total Past Due	996		1,251
Loans Not Past Due	$ 12,873		$ 13,502

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

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