Securities (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Amortized cost and fair value of securities held to maturity
Amortized Cost, Held to Maturity	$ 348,340	$ 317,766
Gross Unrealized Gains, Held to Maturity	7,216	16,976
Gross Unrealized Losses, Held to Maturity	(8,401)	(267)
Fair Value, Held to Maturity	347,155	334,475
Obligations of other U.S. Government agencies and corporations [Member]
Amortized cost and fair value of securities held to maturity
Amortized Cost, Held to Maturity	126,052	90,045
Gross Unrealized Gains, Held to Maturity	0	116
Gross Unrealized Losses, Held to Maturity	(6,049)	(232)
Fair Value, Held to Maturity	120,003	89,929
Obligations of states and political subdivisions [Member]
Amortized cost and fair value of securities held to maturity
Amortized Cost, Held to Maturity	222,288	227,721
Gross Unrealized Gains, Held to Maturity	7,216	16,860
Gross Unrealized Losses, Held to Maturity	(2,352)	(35)
Fair Value, Held to Maturity	$ 227,152	$ 244,546

This item represents the aggregate fair value of investments in debt securities as of the balance sheet date and which are categorized as held-to-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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- Definition

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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