Securities, Held to Maturity (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Held to maturity [Abstract]
Amortized Cost	$ 160,539	$ 143,995
Gross Unrealized Gains	10,523	7,449
Gross Unrealized Losses	216	15
Fair Value	170,846	151,429
Amortized cost of single maturity securities held to maturity [Abstract]
Due in one year or less	3,907
Due after one year through five years	8,537
Due after five years through ten years	13,745
Due after ten years	134,350
Amortized cost, total	160,539
Fair value of single maturity securities held to maturity [Abstract]
Due in one year or less	3,958
Due after one year through five years	8,814
Due after five years through ten years	15,050
Due after ten years	143,024
Fair value, total	170,846
U.S. Government Agencies and Corporations [Member]
Held to maturity [Abstract]
Amortized Cost	7,988	22,057
Gross Unrealized Gains	563	562
Gross Unrealized Losses	0	0
Fair Value	8,551	22,619
State and Political Subdivisions [Member]
Held to maturity [Abstract]
Amortized Cost	151,209	119,381
Gross Unrealized Gains	9,880	6,775
Gross Unrealized Losses	216	15
Fair Value	160,873	126,141
Mortgage-Backed Securities [Member]
Held to maturity [Abstract]
Amortized Cost	691	902
Gross Unrealized Gains	73	94
Gross Unrealized Losses	0	0
Fair Value	764	996
Corporate Debt Securities [Member]
Held to maturity [Abstract]
Amortized Cost	651	1,655
Gross Unrealized Gains	7	18
Gross Unrealized Losses	0	0
Fair Value	$ 658	$ 1,673

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Amount of investments in debt securities categorized as held-to-maturity valued at amortized cost, excludes other than temporary impairment (OTTI).

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Amount of held-to-maturity debt securities at fair value maturing in the sixth fiscal year through the tenth fiscal year following the latest fiscal year.

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Carrying amount of debt securities accounted for as held-to-maturity, net of adjustments including, but not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized, and fair value hedge accounting adjustments, maturing in the fifth through tenth fiscal year following the latest fiscal year.

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Amount of held-to-maturity debt securities at fair value maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year.

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Amount of held-to-maturity debt securities at fair value maturing after the tenth fiscal year following the latest fiscal year.

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This item represents the total of all debt securities grouped by maturity dates, at fair value, which are categorized as held-to-maturity.

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Amount of held-to-maturity debt securities at fair value maturing in the next fiscal year following the latest fiscal year.

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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 investments in debt securities which are categorized as held-to-maturity and that have scheduled maturities more than one year from the balance sheet date or operating cycle, if longer; such investments are normally measured at amortized cost (carrying value) unless circumstances indicate that the value to be recovered from the investment is less than its carried amount. The held-to-maturity category is for those securities that the Company has the positive intent and ability to hold until maturity.

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As of the balance sheet date, the excess of fair value over carrying value (amortized cost) of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding gain.

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As of the balance sheet date, the excess of carrying value (amortized cost) over fair value of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding loss.

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