Investment Securities, Amortized Cost, Estimated Values and Gross Unrealized Gains and Losses (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Available for sale [Abstract]
Amortized Cost	$ 416,245,000	$ 385,781,000
Gross Unrealized Gains	9,834,000	16,795,000
Gross Unrealized Losses	(11,928,000)	(223,000)
Estimated Fair Value	414,151,000	402,353,000
Held to maturity [Abstract]
Estimated Fair Value	7,793,000	8,861,000
Total investment securities [Abstract]
Total Amortized Cost	423,395,000	393,816,000
Total Gross Unrealized Gains	10,477,000	17,621,000
Total Gross Unrealized Losses	(11,928,000)	(223,000)
Total Fair Value	421,944,000	411,214,000
Investment securities pledged	273,000,000	286,000,000
Obligations of States and Political Subdivisions [Member]
Held to maturity [Abstract]
Amortized Cost	7,150,000	8,035,000
Gross Unrealized Gains	643,000	826,000
Gross Unrealized Losses	0	0
Estimated Fair Value	7,793,000	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	109,338,000	65,085,000
Gross Unrealized Gains	0	70,000
Gross Unrealized Losses	(6,828,000)	(77,000)
Estimated Fair Value	102,510,000	65,078,000
Obligations of States and Political Subdivisions [Member]
Available for sale [Abstract]
Amortized Cost	150,955,000	155,121,000
Gross Unrealized Gains	8,828,000	13,314,000
Gross Unrealized Losses	0	0
Estimated Fair Value	159,783,000	168,435,000
Collateralized Mortgage Obligations [Member]
Available for sale [Abstract]
Amortized Cost	36,208,000	87,624,000
Gross Unrealized Gains	716,000	2,148,000
Gross Unrealized Losses	(660,000)	(80,000)
Estimated Fair Value	36,264,000	89,692,000
Mortgage-Backed Securities [Member]
Available for sale [Abstract]
Amortized Cost	104,176,000	61,750,000
Gross Unrealized Gains	31,000	766,000
Gross Unrealized Losses	(4,222,000)	(66,000)
Estimated Fair Value	99,985,000	62,450,000
Corporate Bonds [Member]
Available for sale [Abstract]
Amortized Cost	15,568,000	15,701,000
Gross Unrealized Gains	259,000	497,000
Gross Unrealized Losses	(218,000)	0
Estimated Fair Value	$ 15,609,000	$ 16,198,000