Investments (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Available for sale securities amortized cost unrealized losses and fair value [Abstract]
Amortized Cost	$ 313,117,000		$ 313,117,000		$ 308,806,000
Gross Unrealized Gains	10,214,000		10,214,000		10,056,000
Gross Unrealized Losses	(200,000)		(200,000)		(39,000)
Fair Value	323,131,000		323,131,000		318,823,000
Number of securities owned by the entity, the fair value of which is less than cost	13		13
Available-for-sale securities, fair value and unrealized loss [Abstract]
Total securities, Less than Twelve Months, Fair Value	19,392,000		19,392,000		14,278,000
Total securities, Less than Twelve Months, Gross Unrealized Losses	(200,000)		(200,000)		(37,000)
Total securities, Twelve Months or Greater, Fair Value	0		0		771,000
Total securities, Twelve Months or Greater, Gross Unrealized Losses	0		0		(2,000)
Total securities, Fair Value	19,392,000		19,392,000		15,049,000
Total securities, Gross Unrealized Losses	(200,000)		(200,000)		(39,000)
Proceeds from sale of securities available-for-sale	5,418,000	4,632,000	16,654,000	7,821,000
Realized investment gains (losses) [Abstract]
Gross gains	213,000	114,000	321,000	263,000
Gross losses	0	0		(29,000)
Net gains	213,000	114,000	321,000	234,000
Investment securities pledged to secure public funds and certain other deposits	174,100,000		174,100,000		177,900,000
Amortized Cost [Abstract]
Due in one year or less	15,878,000		15,878,000
Due after one year through five years	83,752,000		83,752,000
Due after five years through ten years	47,862,000		47,862,000
Due after ten years	164,714,000		164,714,000
Total	312,206,000		312,206,000
Fair Value [Abstract]
Due in one year or less	16,028,000		16,028,000
Due after one year through five years	85,499,000		85,499,000
Due after five years through ten years	49,081,000		49,081,000
Due after ten years	171,143,000		171,143,000
Total	321,751,000		321,751,000
U.S. Agency securities [Member]
Available for sale securities amortized cost unrealized losses and fair value [Abstract]
Amortized Cost	144,214,000		144,214,000		166,534,000
Gross Unrealized Gains	2,157,000		2,157,000		2,087,000
Gross Unrealized Losses	(7,000)		(7,000)		(21,000)
Fair Value	146,364,000		146,364,000		168,600,000
Available-for-sale securities, fair value and unrealized loss [Abstract]
Total securities, Less than Twelve Months, Fair Value	4,010,000		4,010,000		10,018,000
Total securities, Less than Twelve Months, Gross Unrealized Losses	(7,000)		(7,000)		(21,000)
Total securities, Twelve Months or Greater, Fair Value	0		0		0
Total securities, Twelve Months or Greater, Gross Unrealized Losses	0		0		0
Total securities, Fair Value	4,010,000		4,010,000		10,018,000
Total securities, Gross Unrealized Losses	(7,000)		(7,000)		(21,000)
Obligations of state and political subdivisions [Member]
Available for sale securities amortized cost unrealized losses and fair value [Abstract]
Amortized Cost	93,130,000		93,130,000		96,556,000
Gross Unrealized Gains	5,089,000		5,089,000		4,996,000
Gross Unrealized Losses	(72,000)		(72,000)		(5,000)
Fair Value	98,147,000		98,147,000		101,547,000
Available-for-sale securities, fair value and unrealized loss [Abstract]
Total securities, Less than Twelve Months, Fair Value	3,437,000		3,437,000		1,057,000
Total securities, Less than Twelve Months, Gross Unrealized Losses	(72,000)		(72,000)		(3,000)
Total securities, Twelve Months or Greater, Fair Value	0		0		771,000
Total securities, Twelve Months or Greater, Gross Unrealized Losses	0		0		(2,000)
Total securities, Fair Value	3,437,000		3,437,000		1,828,000
Total securities, Gross Unrealized Losses	(72,000)		(72,000)		(5,000)
Corporate obligations [Member]
Available for sale securities amortized cost unrealized losses and fair value [Abstract]
Amortized Cost	10,790,000		10,790,000		8,263,000
Gross Unrealized Gains	276,000		276,000		197,000
Gross Unrealized Losses	(20,000)		(20,000)		0
Fair Value	11,046,000		11,046,000		8,460,000
Available-for-sale securities, fair value and unrealized loss [Abstract]
Total securities, Less than Twelve Months, Fair Value	2,585,000		2,585,000
Total securities, Less than Twelve Months, Gross Unrealized Losses	(20,000)		(20,000)
Total securities, Twelve Months or Greater, Fair Value	0		0
Total securities, Twelve Months or Greater, Gross Unrealized Losses	0		0
Total securities, Fair Value	2,585,000		2,585,000
Total securities, Gross Unrealized Losses	(20,000)		(20,000)
Mortgage-backed securities in government sponsored entities [Member]
Available for sale securities amortized cost unrealized losses and fair value [Abstract]
Amortized Cost	64,072,000		64,072,000		36,630,000
Gross Unrealized Gains	2,223,000		2,223,000		2,356,000
Gross Unrealized Losses	(101,000)		(101,000)		(12,000)
Fair Value	66,194,000		66,194,000		38,974,000
Available-for-sale securities, fair value and unrealized loss [Abstract]
Total securities, Less than Twelve Months, Fair Value	9,360,000		9,360,000		3,164,000
Total securities, Less than Twelve Months, Gross Unrealized Losses	(101,000)		(101,000)		(12,000)
Total securities, Twelve Months or Greater, Fair Value	0		0		0
Total securities, Twelve Months or Greater, Gross Unrealized Losses	0		0		0
Total securities, Fair Value	9,360,000		9,360,000		3,164,000
Total securities, Gross Unrealized Losses	(101,000)		(101,000)		(12,000)
Equity securities in financial institutions [Member]
Available for sale securities amortized cost unrealized losses and fair value [Abstract]
Amortized Cost	911,000		911,000		823,000
Gross Unrealized Gains	469,000		469,000		420,000
Gross Unrealized Losses	0		0		(1,000)
Fair Value	1,380,000		1,380,000		1,242,000
Available-for-sale securities, fair value and unrealized loss [Abstract]
Total securities, Less than Twelve Months, Fair Value					39,000
Total securities, Less than Twelve Months, Gross Unrealized Losses					(1,000)
Total securities, Twelve Months or Greater, Fair Value					0
Total securities, Twelve Months or Greater, Gross Unrealized Losses					0
Total securities, Fair Value					39,000
Total securities, Gross Unrealized Losses					$ (1,000)