Fair Value of Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Investment Securities Available-for-Sale: [Abstract]
Total Investment Securities Available-for-Sale	$ 463,177	$ 479,820	$ 420,809
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets: [Abstract]
Cash and Cash Equivalents	33,464
Investment Securities Available-for-Sale: [Abstract]
Government Agency & Government-Sponsored Entities	10,627
Obligations of States and Political Subdivisions	0
Mortgage Backed Securities	0
Corporate Bonds	0
Other	5,516
Total Investment Securities Available-for-Sale	16,143
Investment Securities Held-to-Maturity: [Abstract]
Obligations of States and Political Subdivisions	0
Mortgage Backed Securities	0
Other	0
Total Investment Securities Held-to-Maturity	0
Loans, Net of Deferred Loan Fees & Allowance: [Abstract]
Commercial Real Estate	0
Agricultural Real Estate	0
Real Estate Construction	0
Residential 1st Mortgages	0
Home Equity Lines and Loans	0
Agricultural	0
Commercial	0
Consumer & Other	0
Unallocated Allowance	0
Total Loans, Net of Deferred Loan Fees & Allowance	0
Accrued Interest Receivable	0
Deposits:
Demand	369,635
Interest Bearing Transaction	238,223
Savings and Money Market	540,690
Time	0
Total Deposits	1,148,548
FHLB Advances & Securities Sold Under Agreement to Repurchase	0
Subordinated Debentures	0
Accrued Interest Payable	0
Other Observable Inputs (Level 2) [Member]
Assets: [Abstract]
Cash and Cash Equivalents	0
Investment Securities Available-for-Sale: [Abstract]
Government Agency & Government-Sponsored Entities	36,344
Obligations of States and Political Subdivisions	0
Mortgage Backed Securities	389,812
Corporate Bonds	14,864
Other	310
Total Investment Securities Available-for-Sale	441,330
Investment Securities Held-to-Maturity: [Abstract]
Obligations of States and Political Subdivisions	60,983
Mortgage Backed Securities	660
Other	2,222
Total Investment Securities Held-to-Maturity	63,865
Loans, Net of Deferred Loan Fees & Allowance: [Abstract]
Commercial Real Estate	0
Agricultural Real Estate	0
Real Estate Construction	0
Residential 1st Mortgages	0
Home Equity Lines and Loans	0
Agricultural	0
Commercial	0
Consumer & Other	0
Unallocated Allowance	0
Total Loans, Net of Deferred Loan Fees & Allowance	0
Accrued Interest Receivable	0
Deposits:
Demand	0
Interest Bearing Transaction	0
Savings and Money Market	0
Time	483,950
Total Deposits	483,950
FHLB Advances & Securities Sold Under Agreement to Repurchase	547
Subordinated Debentures	5,478
Accrued Interest Payable	526
Significant Unobservable Inputs (Level 3) [Member]
Assets: [Abstract]
Cash and Cash Equivalents	0
Investment Securities Available-for-Sale: [Abstract]
Government Agency & Government-Sponsored Entities	0
Obligations of States and Political Subdivisions	5,704
Mortgage Backed Securities	0
Corporate Bonds	0
Other	0
Total Investment Securities Available-for-Sale	5,704
Investment Securities Held-to-Maturity: [Abstract]
Obligations of States and Political Subdivisions	7,738
Mortgage Backed Securities	0
Other	0
Total Investment Securities Held-to-Maturity	7,738
Loans, Net of Deferred Loan Fees & Allowance: [Abstract]
Commercial Real Estate	340,570
Agricultural Real Estate	298,168
Real Estate Construction	31,236
Residential 1st Mortgages	141,334
Home Equity Lines and Loans	43,243
Agricultural	184,647
Commercial	157,440
Consumer & Other	5,454
Unallocated Allowance	(628)
Total Loans, Net of Deferred Loan Fees & Allowance	1,201,464
Accrued Interest Receivable	8,037
Deposits:
Demand	0
Interest Bearing Transaction	0
Savings and Money Market	0
Time	0
Total Deposits	0
FHLB Advances & Securities Sold Under Agreement to Repurchase	0
Subordinated Debentures	0
Accrued Interest Payable	0
Carrying Amount [Member]
Assets: [Abstract]
Cash and Cash Equivalents	33,464	101,660	112,611
Investment Securities Available-for-Sale: [Abstract]
Government Agency & Government-Sponsored Entities	46,971
Obligations of States and Political Subdivisions	5,704
Mortgage Backed Securities	389,812
Corporate Bonds	14,864
Other	5,826
Total Investment Securities Available-for-Sale	463,177	479,820	420,809
Investment Securities Held-to-Maturity: [Abstract]
Obligations of States and Political Subdivisions	66,098
Mortgage Backed Securities	640
Other	2,222
Total Investment Securities Held-to-Maturity	68,960	63,092	63,803
FHLB Stock	7,368	7,035	7,035
Loans, Net of Deferred Loan Fees & Allowance: [Abstract]
Commercial Real Estate	331,331
Agricultural Real Estate	290,202
Real Estate Construction	30,840
Residential 1st Mortgages	135,922
Home Equity Lines and Loans	40,475
Agricultural	184,794
Commercial	158,117
Consumer & Other	5,370
Unallocated Allowance	(628)
Total Loans, Net of Deferred Loan Fees & Allowance	1,176,423	1,130,061	1,144,542
Accrued Interest Receivable	8,037	6,368	7,454
Deposits:
Demand	369,635	389,639	359,649
Interest Bearing Transaction	238,223	1,236,558	1,229,639
Savings and Money Market	540,690
Time	482,957
Total Deposits	1,631,505
FHLB Advances & Securities Sold Under Agreement to Repurchase	482	60,530	60,546
Subordinated Debentures	10,310	10,310	10,310
Accrued Interest Payable	526	911	907
Estimated Fair Value [Member]
Assets: [Abstract]
Cash and Cash Equivalents	33,464	101,660	112,611
Investment Securities Available-for-Sale: [Abstract]
Government Agency & Government-Sponsored Entities	46,971
Obligations of States and Political Subdivisions	5,704
Mortgage Backed Securities	389,812
Corporate Bonds	14,864
Other	5,826
Total Investment Securities Available-for-Sale	463,177	479,820	420,809
Investment Securities Held-to-Maturity: [Abstract]
Obligations of States and Political Subdivisions	68,721
Mortgage Backed Securities	660
Other	2,222
Total Investment Securities Held-to-Maturity	71,603	65,874	66,302
Loans, Net of Deferred Loan Fees & Allowance: [Abstract]
Commercial Real Estate	340,570
Agricultural Real Estate	298,168
Real Estate Construction	31,236
Residential 1st Mortgages	141,334
Home Equity Lines and Loans	43,243
Agricultural	184,647
Commercial	157,440
Consumer & Other	5,454
Unallocated Allowance	(628)
Total Loans, Net of Deferred Loan Fees & Allowance	1,201,464	1,162,261	1,183,033
Accrued Interest Receivable	8,037	6,368	7,454
Deposits:
Demand	369,635	389,639	359,649
Interest Bearing Transaction	238,223	1,237,849	1,231,089
Savings and Money Market	540,690
Time	483,950
Total Deposits	1,632,498
FHLB Advances & Securities Sold Under Agreement to Repurchase	547	63,000	63,626
Subordinated Debentures	5,478	5,953	5,751
Accrued Interest Payable	$ 526	$ 911	$ 907

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