Loans & Leases and Allowance for Credit Losses, Loan Portfolio Allocated by Management's Internal Risk Ratings (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	$ 1,705,320	$ 1,712,244	$ 1,363,030
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	529,550	491,903	402,865
Agricultural Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	351,866	357,207	326,112
Real Estate Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	101,616	96,519	55,751
Residential 1st Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	182,431	171,880	156,094
Home Equity Lines & Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	31,724	33,017	34,289
Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	216,231	281,963	209,228
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	236,141	230,819	155,802
Consumer & Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	4,915	4,719	4,721
Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	50,846	44,217	18,168
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	1,675,723	1,678,690	1,325,667
Pass [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	520,613	483,146	389,366
Pass [Member] | Agricultural Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	351,866	357,207	326,112
Pass [Member] | Real Estate Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	99,920	94,887	54,120
Pass [Member] | Residential 1st Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	181,021	170,462	154,743
Pass [Member] | Home Equity Lines & Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	30,772	32,054	33,196
Pass [Member] | Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	215,507	281,232	208,308
Pass [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	220,491	211,036	137,125
Pass [Member] | Consumer & Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	4,687	4,449	4,529
Pass [Member] | Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	50,846	44,217	18,168
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	23,896	29,934	33,295
Special Mention [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	8,834	8,651	13,126
Special Mention [Member] | Agricultural Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	0	0	0
Special Mention [Member] | Real Estate Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	1,696	1,632	1,631
Special Mention [Member] | Residential 1st Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	744	744	767
Special Mention [Member] | Home Equity Lines & Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	83	85	0
Special Mention [Member] | Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	453	679	843
Special Mention [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	12,086	18,143	16,928
Special Mention [Member] | Consumer & Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	0	0	0
Special Mention [Member] | Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases		0
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	5,701	3,620	4,068
Substandard [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	103	106	373
Substandard [Member] | Agricultural Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	0	0	0
Substandard [Member] | Real Estate Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	0	0	0
Substandard [Member] | Residential 1st Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	666	674	584
Substandard [Member] | Home Equity Lines & Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	869	878	1,093
Substandard [Member] | Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	271	52	77
Substandard [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	3,564	1,640	1,749
Substandard [Member] | Consumer & Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	228	270	192
Substandard [Member] | Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases		0
Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	0	0	0
Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & leases	$ 0	$ 0	$ 0