Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands		Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Assets [Abstract]
Available-for-Sale Securities		$ 341,771	$ 369,137	$ 365,184
Investment Securities Held-to-Maturity		62,892	62,388	64,218
Obligations of States and Political Subdivisions [Member]
Assets [Abstract]
Investment Securities Held-to-Maturity		62,892	62,388	62,079
Other [Member]
Assets [Abstract]
Investment Securities Held-to-Maturity				2,139
Government Agency & Government-Sponsored Entities [Member]
Assets [Abstract]
Available-for-Sale Securities		63,346	33,251	68,132
US Treasury Notes [Member]
Assets [Abstract]
Available-for-Sale Securities		65,788	72,884	19,966
Mortgage Backed Securities [Member]
Assets [Abstract]
Available-for-Sale Securities	[1]	212,127	262,493	276,601
Other [Member]
Assets [Abstract]
Available-for-Sale Securities		510	509	485
Carrying Amount [Member]
Assets [Abstract]
Cash and Cash Equivalents		73,716	59,446	143,936
Available-for-Sale Securities		341,771	369,137	365,184
Investment Securities Held-to-Maturity		61,535	61,396	63,463
FHLB Stock		7,795	7,795	7,677
Loans & Leases, Net of Deferred Fees & Allowance		1,948,942	1,954,836	1,666,380
Accrued Interest Receivable		8,118	9,240	7,324
Liabilities [Abstract]
Deposits		2,256,464	2,277,532	2,111,773
Subordinated Debentures		10,310	10,310	10,310
Accrued Interest Payable		471	513	433
Carrying Amount [Member] | Demand [Member]
Liabilities [Abstract]
Deposits		637,140	711,029	578,820
Carrying Amount [Member] | Interest Bearing Transaction [Member]
Liabilities [Abstract]
Deposits		409,360	377,594	340,045
Carrying Amount [Member] | Savings and Money Market [Member]
Liabilities [Abstract]
Deposits		725,823	707,885	699,308
Carrying Amount [Member] | Time [Member]
Liabilities [Abstract]
Deposits		484,141	481,024	493,600
Carrying Amount [Member] | Commercial Real Estate [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		601,412	593,587	521,596
Carrying Amount [Member] | Agricultural Real Estate [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		423,119	417,153	344,965
Carrying Amount [Member] | Real Estate Construction [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		163,861	149,489	99,700
Carrying Amount [Member] | Residential 1st Mortgages [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		211,409	205,616	181,758
Carrying Amount [Member] | Home Equity Lines and Loans [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		29,575	30,910	29,628
Carrying Amount [Member] | Agricultural [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		247,751	287,658	211,629
Carrying Amount [Member] | Commercial [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		205,754	202,968	227,200
Carrying Amount [Member] | Consumer & Other [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		6,879	6,417	4,703
Carrying Amount [Member] | Leases [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		61,541	62,584	48,347
Carrying Amount [Member] | Unallocated Allowance [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		(2,359)	(1,546)	(3,146)
Carrying Amount [Member] | Obligations of States and Political Subdivisions [Member]
Assets [Abstract]
Investment Securities Held-to-Maturity		61,535	61,396	61,324
Carrying Amount [Member] | Other [Member]
Assets [Abstract]
Investment Securities Held-to-Maturity				2,139
Carrying Amount [Member] | Government Agency & Government-Sponsored Entities [Member]
Assets [Abstract]
Available-for-Sale Securities		63,346	33,251	68,132
Carrying Amount [Member] | US Treasury Notes [Member]
Assets [Abstract]
Available-for-Sale Securities		65,788	72,884	19,966
Carrying Amount [Member] | Mortgage Backed Securities [Member]
Assets [Abstract]
Available-for-Sale Securities		212,127	262,493	276,601
Carrying Amount [Member] | Other [Member]
Assets [Abstract]
Available-for-Sale Securities		510	509	485
Estimated Fair Value [Member]
Assets [Abstract]
Cash and Cash Equivalents		73,716	59,446	143,936
Available-for-Sale Securities		341,771	369,137	365,184
Investment Securities Held-to-Maturity		62,892	62,388	64,218
Loans & Leases, Net of Deferred Fees & Allowance		1,947,030	1,939,575	1,668,775
Accrued Interest Receivable		8,118	9,240	7,324
Liabilities [Abstract]
Deposits		2,256,112	2,276,842	2,111,773
Subordinated Debentures		6,437	6,424	6,250
Accrued Interest Payable		471	513	433
Estimated Fair Value [Member] | Demand [Member]
Liabilities [Abstract]
Deposits		637,140	711,029	578,820
Estimated Fair Value [Member] | Interest Bearing Transaction [Member]
Liabilities [Abstract]
Deposits		409,361	377,594	340,045
Estimated Fair Value [Member] | Savings and Money Market [Member]
Liabilities [Abstract]
Deposits		725,822	707,885	699,308
Estimated Fair Value [Member] | Time [Member]
Liabilities [Abstract]
Deposits		483,789	480,334	493,600
Estimated Fair Value [Member] | Commercial Real Estate [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		604,707	591,271	519,698
Estimated Fair Value [Member] | Agricultural Real Estate [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		414,223	405,295	346,742
Estimated Fair Value [Member] | Real Estate Construction [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		163,917	149,371	99,861
Estimated Fair Value [Member] | Residential 1st Mortgages [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		214,885	207,431	185,210
Estimated Fair Value [Member] | Home Equity Lines and Loans [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		30,806	32,360	31,332
Estimated Fair Value [Member] | Agricultural [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		246,626	285,733	210,769
Estimated Fair Value [Member] | Commercial [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		204,828	201,105	224,783
Estimated Fair Value [Member] | Consumer & Other [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		6,938	6,416	4,747
Estimated Fair Value [Member] | Leases [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		62,459	62,139	48,779
Estimated Fair Value [Member] | Unallocated Allowance [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		(2,359)	(1,546)	(3,146)
Estimated Fair Value [Member] | Obligations of States and Political Subdivisions [Member]
Assets [Abstract]
Investment Securities Held-to-Maturity		62,892	62,388	62,079
Estimated Fair Value [Member] | Other [Member]
Assets [Abstract]
Investment Securities Held-to-Maturity				2,139
Estimated Fair Value [Member] | Government Agency & Government-Sponsored Entities [Member]
Assets [Abstract]
Available-for-Sale Securities		63,346	33,251	68,132
Estimated Fair Value [Member] | US Treasury Notes [Member]
Assets [Abstract]
Available-for-Sale Securities		65,788	72,884	19,966
Estimated Fair Value [Member] | Mortgage Backed Securities [Member]
Assets [Abstract]
Available-for-Sale Securities		212,127	262,493	276,601
Estimated Fair Value [Member] | Other [Member]
Assets [Abstract]
Available-for-Sale Securities		510	509	485
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets [Abstract]
Cash and Cash Equivalents		73,716	59,446	143,936
Available-for-Sale Securities		65,988	73,083	175
Investment Securities Held-to-Maturity		0	0	0
Loans & Leases, Net of Deferred Fees & Allowance		0	0	0
Accrued Interest Receivable		0	0	0
Liabilities [Abstract]
Deposits		1,772,323	1,796,508	1,618,173
Subordinated Debentures		0	0	0
Accrued Interest Payable		0	0	0
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Demand [Member]
Liabilities [Abstract]
Deposits		637,140	711,029	578,820
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Interest Bearing Transaction [Member]
Liabilities [Abstract]
Deposits		409,361	377,594	340,045
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Savings and Money Market [Member]
Liabilities [Abstract]
Deposits		725,822	707,885	699,308
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Time [Member]
Liabilities [Abstract]
Deposits		0	0	0
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Commercial Real Estate [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		0	0	0
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Agricultural Real Estate [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		0	0	0
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Real Estate Construction [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		0	0	0
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Residential 1st Mortgages [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		0	0	0
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Home Equity Lines and Loans [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		0	0	0
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Agricultural [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		0	0	0
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Commercial [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		0	0	0
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Consumer & Other [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		0	0	0
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Leases [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		0	0	0
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Unallocated Allowance [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		0	0	0
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Obligations of States and Political Subdivisions [Member]
Assets [Abstract]
Investment Securities Held-to-Maturity		0	0	0
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other [Member]
Assets [Abstract]
Investment Securities Held-to-Maturity				0
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Government Agency & Government-Sponsored Entities [Member]
Assets [Abstract]
Available-for-Sale Securities		0	0	0
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | US Treasury Notes [Member]
Assets [Abstract]
Available-for-Sale Securities		65,788	72,884	0
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Mortgage Backed Securities [Member]
Assets [Abstract]
Available-for-Sale Securities		0	0	0
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other [Member]
Assets [Abstract]
Available-for-Sale Securities		200	199	175
Estimated Fair Value [Member] | Other Observable Inputs (Level 2) [Member]
Assets [Abstract]
Cash and Cash Equivalents		0	0	0
Available-for-Sale Securities		275,783	296,054	365,009
Investment Securities Held-to-Maturity		50,436	44,675	50,722
Loans & Leases, Net of Deferred Fees & Allowance		0	0	0
Accrued Interest Receivable		8,118	9,240	7,324
Liabilities [Abstract]
Deposits		483,789	480,334	493,600
Subordinated Debentures		6,437	6,424	6,250
Accrued Interest Payable		471	513	433
Estimated Fair Value [Member] | Other Observable Inputs (Level 2) [Member] | Demand [Member]
Liabilities [Abstract]
Deposits		0	0	0
Estimated Fair Value [Member] | Other Observable Inputs (Level 2) [Member] | Interest Bearing Transaction [Member]
Liabilities [Abstract]
Deposits		0	0	0
Estimated Fair Value [Member] | Other Observable Inputs (Level 2) [Member] | Savings and Money Market [Member]
Liabilities [Abstract]
Deposits		0	0	0
Estimated Fair Value [Member] | Other Observable Inputs (Level 2) [Member] | Time [Member]
Liabilities [Abstract]
Deposits		483,789	480,334	493,600
Estimated Fair Value [Member] | Other Observable Inputs (Level 2) [Member] | Commercial Real Estate [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		0	0	0
Estimated Fair Value [Member] | Other Observable Inputs (Level 2) [Member] | Agricultural Real Estate [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		0	0	0
Estimated Fair Value [Member] | Other Observable Inputs (Level 2) [Member] | Real Estate Construction [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		0	0	0
Estimated Fair Value [Member] | Other Observable Inputs (Level 2) [Member] | Residential 1st Mortgages [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		0	0	0
Estimated Fair Value [Member] | Other Observable Inputs (Level 2) [Member] | Home Equity Lines and Loans [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		0	0	0
Estimated Fair Value [Member] | Other Observable Inputs (Level 2) [Member] | Agricultural [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		0	0	0
Estimated Fair Value [Member] | Other Observable Inputs (Level 2) [Member] | Commercial [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		0	0	0
Estimated Fair Value [Member] | Other Observable Inputs (Level 2) [Member] | Consumer & Other [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		0	0	0
Estimated Fair Value [Member] | Other Observable Inputs (Level 2) [Member] | Leases [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		0	0	0
Estimated Fair Value [Member] | Other Observable Inputs (Level 2) [Member] | Unallocated Allowance [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		0	0	0
Estimated Fair Value [Member] | Other Observable Inputs (Level 2) [Member] | Obligations of States and Political Subdivisions [Member]
Assets [Abstract]
Investment Securities Held-to-Maturity		50,436	44,675	48,583
Estimated Fair Value [Member] | Other Observable Inputs (Level 2) [Member] | Other [Member]
Assets [Abstract]
Investment Securities Held-to-Maturity				2,139
Estimated Fair Value [Member] | Other Observable Inputs (Level 2) [Member] | Government Agency & Government-Sponsored Entities [Member]
Assets [Abstract]
Available-for-Sale Securities		63,346	33,251	68,132
Estimated Fair Value [Member] | Other Observable Inputs (Level 2) [Member] | US Treasury Notes [Member]
Assets [Abstract]
Available-for-Sale Securities		0	0	19,966
Estimated Fair Value [Member] | Other Observable Inputs (Level 2) [Member] | Mortgage Backed Securities [Member]
Assets [Abstract]
Available-for-Sale Securities		212,127	262,493	276,601
Estimated Fair Value [Member] | Other Observable Inputs (Level 2) [Member] | Other [Member]
Assets [Abstract]
Available-for-Sale Securities		310	310	310
Estimated Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets [Abstract]
Cash and Cash Equivalents		0	0	0
Available-for-Sale Securities		0	0	0
Investment Securities Held-to-Maturity		12,456	17,713	13,496
Loans & Leases, Net of Deferred Fees & Allowance		1,947,030	1,939,575	1,668,775
Accrued Interest Receivable		0	0	0
Liabilities [Abstract]
Deposits		0	0	0
Subordinated Debentures		0	0	0
Accrued Interest Payable		0	0	0
Estimated Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | Demand [Member]
Liabilities [Abstract]
Deposits		0	0	0
Estimated Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | Interest Bearing Transaction [Member]
Liabilities [Abstract]
Deposits		0	0	0
Estimated Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | Savings and Money Market [Member]
Liabilities [Abstract]
Deposits		0	0	0
Estimated Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | Time [Member]
Liabilities [Abstract]
Deposits		0	0	0
Estimated Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | Commercial Real Estate [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		604,707	591,271	519,698
Estimated Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | Agricultural Real Estate [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		414,223	405,295	346,742
Estimated Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | Real Estate Construction [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		163,917	149,371	99,861
Estimated Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | Residential 1st Mortgages [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		214,885	207,431	185,210
Estimated Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | Home Equity Lines and Loans [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		30,806	32,360	31,332
Estimated Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | Agricultural [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		246,626	285,733	210,769
Estimated Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | Commercial [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		204,828	201,105	224,783
Estimated Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | Consumer & Other [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		6,938	6,416	4,747
Estimated Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | Leases [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		62,459	62,139	48,779
Estimated Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | Unallocated Allowance [Member]
Assets [Abstract]
Loans & Leases, Net of Deferred Fees & Allowance		(2,359)	(1,546)	(3,146)
Estimated Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | Obligations of States and Political Subdivisions [Member]
Assets [Abstract]
Investment Securities Held-to-Maturity		12,456	17,713	13,496
Estimated Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other [Member]
Assets [Abstract]
Investment Securities Held-to-Maturity				0
Estimated Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | Government Agency & Government-Sponsored Entities [Member]
Assets [Abstract]
Available-for-Sale Securities		0	0	0
Estimated Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | US Treasury Notes [Member]
Assets [Abstract]
Available-for-Sale Securities		0	0	0
Estimated Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | Mortgage Backed Securities [Member]
Assets [Abstract]
Available-for-Sale Securities		0	0	0
Estimated Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other [Member]
Assets [Abstract]
Available-for-Sale Securities		$ 0	$ 0	$ 0

[1] All Mortgage Backed Securities consist of securities collateralized by residential real estate and were issued by an agency or government sponsored entity of the U.S. government.