Loans & Leases and Allowance for Credit Losses, Loan Portfolio Allocated by Management's Internal Risk Ratings (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	$ 1,615,771	$ 1,388,236	$ 1,297,811
Loans outstanding rated doubtful or loss	0	0	0
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	473,505	407,514	401,626
Agricultural Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	364,161	328,264	311,401
Real Estate Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	104,463	41,092	27,099
Residential 1st Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	168,310	151,292	143,577
Home Equity Lines & Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	33,283	35,477	37,160
Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	237,521	256,414	221,569
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	192,804	150,398	145,793
Consumer & Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	4,816	5,052	5,063
Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	36,908	12,733	4,523
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	1,577,302	1,353,440	1,265,557
Pass [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	464,714	398,488	389,137
Pass [Member] | Agricultural Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	364,161	325,926	307,736
Pass [Member] | Real Estate Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	102,831	39,460	25,467
Pass [Member] | Residential 1st Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	166,884	149,798	142,036
Pass [Member] | Home Equity Lines & Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	32,309	34,821	36,090
Pass [Member] | Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	236,760	255,443	220,504
Pass [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	168,215	132,008	135,303
Pass [Member] | Consumer & Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	4,520	4,763	4,761
Pass [Member] | Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	36,908	12,733	4,523
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	34,779	29,038	22,096
Special Mention [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	8,683	7,979	7,765
Special Mention [Member] | Agricultural Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	0	2,338	2,497
Special Mention [Member] | Real Estate Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	1,632	1,632	1,632
Special Mention [Member] | Residential 1st Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	752	774	780
Special Mention [Member] | Home Equity Lines & Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	88	0	0
Special Mention [Member] | Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	695	889	464
Special Mention [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	22,929	15,426	8,958
Special Mention [Member] | Consumer & Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	0	0	0
Special Mention [Member] | Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	0	0	0
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	3,690	5,758	10,158
Substandard [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	108	1,047	4,724
Substandard [Member] | Agricultural Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	0	0	1,168
Substandard [Member] | Real Estate Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	0	0	0
Substandard [Member] | Residential 1st Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	674	720	761
Substandard [Member] | Home Equity Lines & Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	886	656	1,070
Substandard [Member] | Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	66	82	601
Substandard [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	1,660	2,964	1,532
Substandard [Member] | Consumer & Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	296	289	302
Substandard [Member] | Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans & lease	$ 0	$ 0	$ 0