Investment Securities, Amortized Cost, Estimated Values and Gross Unrealized Gains and Losses (Details) (USD $)	Mar. 31, 2013	Dec. 31, 2012
Available for sale [Abstract]
Amortized Cost	$ 398,621,000	$ 385,781,000
Gross Unrealized Gains	15,221,000	16,795,000
Gross Unrealized Losses	(565,000)	(223,000)
Estimated Fair Value	413,277,000	402,353,000
Held to maturity [Abstract]
Estimated Fair Value	8,662,000	8,861,000
Total investment securities [Abstract]
Total Amortized Cost	406,492,000	393,816,000
Total Gross Unrealized Gains	16,012,000	17,621,000
Total Gross Unrealized Losses	(565,000)	(223,000)
Total Fair Value	421,939,000	411,214,000
Investment securities pledged	278,000,000	286,000,000
Obligations of States and Political Subdivisions [Member]
Held to maturity [Abstract]
Amortized Cost	7,871,000	8,035,000
Gross Unrealized Gains	791,000	826,000
Gross Unrealized Losses	0	0
Estimated Fair Value	8,662,000	8,861,000
U.S. Treasury Securities [Member]
Available for sale [Abstract]
Amortized Cost	0	500,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	0	500,000
U.S. Government Agency Securities [Member]
Available for sale [Abstract]
Amortized Cost	75,533,000	65,085,000
Gross Unrealized Gains	59,000	70,000
Gross Unrealized Losses	(204,000)	(77,000)
Estimated Fair Value	75,388,000	65,078,000
Obligations of States and Political Subdivisions [Member]
Available for sale [Abstract]
Amortized Cost	153,701,000	155,121,000
Gross Unrealized Gains	12,851,000	13,314,000
Gross Unrealized Losses	0	0
Estimated Fair Value	166,552,000	168,435,000
Collateralized Mortgage Obligations [Member]
Available for sale [Abstract]
Amortized Cost	64,724,000	87,624,000
Gross Unrealized Gains	1,449,000	2,148,000
Gross Unrealized Losses	(69,000)	(80,000)
Estimated Fair Value	66,104,000	89,692,000
Mortgage-Backed Securities [Member]
Available for sale [Abstract]
Amortized Cost	86,156,000	61,750,000
Gross Unrealized Gains	500,000	766,000
Gross Unrealized Losses	(277,000)	(66,000)
Estimated Fair Value	86,379,000	62,450,000
Corporate Bonds [Member]
Available for sale [Abstract]
Amortized Cost	18,507,000	15,701,000
Gross Unrealized Gains	362,000	497,000
Gross Unrealized Losses	(15,000)	0
Estimated Fair Value	$ 18,854,000	$ 16,198,000

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Debt securities fair value.

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Amount of debt securities categorized neither as held-to-maturity nor trading.

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