Fair Value Measurements (Details) (USD $)	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Other Real Estate [Abstract]
Impaired loans with a partial charge-off or where an allowance was established	$ 3,000,000	$ 335,000	$ 1,700,000
ORE, valuation allowance	4,100,000	4,100,000	4,100,000
Allowance for loan losses	1,706,000	1,081,000	1,374,000
Fair Value, Measurements, Recurring [Member] \| Fair Value [Member]
Available-for-Sale Securities [Abstract]
Government Agency & Government-Sponsored Entities	26,692,000	67,342,000	26,823,000
Obligations of States and Political Subdivisions	5,643,000	5,753,000	5,665,000
Mortgage Backed Securities	432,285,000	448,311,000	352,772,000
Corporate Securities	50,128,000	344,000	22,558,000
Other	825,000	10,067,000	10,173,000
Total Assets Measured at Fair Value On a Recurring Basis	515,573,000	531,817,000	417,991,000
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Available-for-Sale Securities [Abstract]
Government Agency & Government-Sponsored Entities	21,612,000	20,970,000	21,731,000
Obligations of States and Political Subdivisions	0	0	0
Mortgage Backed Securities	0	0	0
Corporate Securities	9,373,000	0	4,020,000
Other	515,000	9,657,000	9,863,000
Total Assets Measured at Fair Value On a Recurring Basis	31,500,000	30,627,000	35,614,000
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Available-for-Sale Securities [Abstract]
Government Agency & Government-Sponsored Entities	5,080,000	46,372,000	5,092,000
Obligations of States and Political Subdivisions	0	0	0
Mortgage Backed Securities	432,285,000	448,311,000	352,772,000
Corporate Securities	40,755,000	344,000	18,538,000
Other	310,000	410,000	310,000
Total Assets Measured at Fair Value On a Recurring Basis	478,430,000	495,437,000	376,712,000
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Available-for-Sale Securities [Abstract]
Government Agency & Government-Sponsored Entities	0	0	0
Obligations of States and Political Subdivisions	5,643,000	5,753,000	5,665,000
Mortgage Backed Securities	0	0	0
Corporate Securities	0	0	0
Other	0	0	0
Total Assets Measured at Fair Value On a Recurring Basis	5,643,000	5,753,000	5,665,000
Changes in level 3 assets measured at fair value on a recurring basis [Roll Forward]
Balance at Beginning of Period	5,665,000	5,782,000
Total Realized and Unrealized Gains/(Losses) Included in Income	0	0
Total Unrealized Gains/(Losses) Included in Other Comprehensive Income	0	0
Purchase of Securities	0	0
Sales, Maturities, and Calls of Securities	(22,000)	(29,000)
Net Transfers In/(Out) of Level 3	0	0
Balance at End of Period	5,643,000	5,753,000
Fair Value, Measurements, Nonrecurring [Member] \| Fair Value [Member]
Impaired Loans [Abstract]
Agricultural Real Estate	1,572,000
Commercial Real Estate		61,000
Residential 1st Mortgage	289,000		235,000
Home Equity Lines and Loans	15,000	225,000	462,000
Agricultural	965,000		1,010,000
Commercial	220,000	49,000
Total Impaired Loans	3,061,000	335,000	1,707,000
Other Real Estate [Abstract]
Real Estate Construction	2,553,000	2,553,000	2,553,000
Agricultural Real Estate	1,910,000
Agricultural	280,000
Residential 1st Mortgage		371,000
Total Other Real Estate	4,743,000	2,924,000	2,553,000
Total Assets Measured at Fair Value On a Non-Recurring Basis	7,804,000	3,259,000	4,260,000
Fair Value, Measurements, Nonrecurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Impaired Loans [Abstract]
Agricultural Real Estate	0
Commercial Real Estate		0
Residential 1st Mortgage	0		0
Home Equity Lines and Loans	0	0	0
Agricultural	0		0
Commercial	0	0
Total Impaired Loans	0	0	0
Other Real Estate [Abstract]
Real Estate Construction	0	0	0
Agricultural Real Estate	0
Agricultural	0
Residential 1st Mortgage		0
Total Other Real Estate	0	0	0
Total Assets Measured at Fair Value On a Non-Recurring Basis	0	0	0
Fair Value, Measurements, Nonrecurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Impaired Loans [Abstract]
Agricultural Real Estate	0
Commercial Real Estate		0
Residential 1st Mortgage	0		0
Home Equity Lines and Loans	0	0	0
Agricultural	0		0
Commercial	0	0
Total Impaired Loans	0	0	0
Other Real Estate [Abstract]
Real Estate Construction	0	0	0
Agricultural Real Estate	0
Agricultural	0
Residential 1st Mortgage		0
Total Other Real Estate	0	0	0
Total Assets Measured at Fair Value On a Non-Recurring Basis	0	0	0
Fair Value, Measurements, Nonrecurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Impaired Loans [Abstract]
Agricultural Real Estate	1,572,000
Commercial Real Estate		61,000
Residential 1st Mortgage	289,000		235,000
Home Equity Lines and Loans	15,000	225,000	462,000
Agricultural	965,000		1,010,000
Commercial	220,000	49,000
Total Impaired Loans	3,061,000	335,000	1,707,000
Other Real Estate [Abstract]
Real Estate Construction	2,553,000	2,553,000	2,553,000
Agricultural Real Estate	1,910,000
Agricultural	280,000
Residential 1st Mortgage		371,000
Total Other Real Estate	4,743,000	2,924,000	2,553,000
Total Assets Measured at Fair Value On a Non-Recurring Basis	$ 7,804,000	$ 3,259,000	$ 4,260,000

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Fair value disclosure of other real estate related to Agricultural Other Real Estate.

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Fair value disclosure for other real estate related to loans secured by farmland.

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Fair value disclosure of secured and unsecured loans for purposes such as seasonal working capital needs, inventory financing, equipment purchases and acquisitions.

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Fair value disclosure of loans solely used for business purposes.

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Fair value disclosure of revolving, open-end loan extended under a line of credit and secured by the borrower's residential property.

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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

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Amount of gain (loss) recognized in earnings, arising from assets measured at fair value on a recurring basis using unobservable inputs (level 3).

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Purchases that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy.

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