Investments (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Available for sale securities amortized cost unrealized losses and fair value [Abstract]
Amortized Cost	$ 310,543,000		$ 310,543,000		$ 308,806,000
Gross Unrealized Gains	11,685,000		11,685,000		10,056,000
Gross Unrealized Losses	(189,000)		(189,000)		(39,000)
Fair Value	322,039,000		322,039,000		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	15,140,000		15,140,000		14,278,000
Total securities, Less than Twelve Months, Gross Unrealized Losses	(189,000)		(189,000)		(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	15,140,000		15,140,000		15,049,000
Total securities, Gross Unrealized Losses	(189,000)		(189,000)		(39,000)
Proceeds from sale of securities available-for-sale	1,709,000	1,969,000	18,363,000	9,790,000
Realized investment gains (losses) [Abstract]
Gross gains	240,000	161,000	561,000	424,000
Gross losses	0	(44,000)	0	(73,000)
Net gains	240,000	117,000	561,000	351,000
Investment securities pledged to secure public funds and certain other deposits	187,700,000		187,700,000		177,900,000
Amortized Cost [Abstract]
Due in one year or less	13,859,000		13,859,000
Due after one year through five years	79,805,000		79,805,000
Due after five years through ten years	58,504,000		58,504,000
Due after ten years	157,464,000		157,464,000
Total	309,632,000		309,632,000
Fair Value [Abstract]
Due in one year or less	13,994,000		13,994,000
Due after one year through five years	81,870,000		81,870,000
Due after five years through ten years	59,913,000		59,913,000
Due after ten years	164,889,000		164,889,000
Total	320,666,000		320,666,000
U.S. Agency securities [Member]
Available for sale securities amortized cost unrealized losses and fair value [Abstract]
Amortized Cost	146,660,000		146,660,000		166,534,000
Gross Unrealized Gains	2,443,000		2,443,000		2,087,000
Gross Unrealized Losses	(6,000)		(6,000)		(21,000)
Fair Value	149,097,000		149,097,000		168,600,000
Available-for-sale securities, fair value and unrealized loss [Abstract]
Total securities, Less than Twelve Months, Fair Value	4,994,000		4,994,000		10,018,000
Total securities, Less than Twelve Months, Gross Unrealized Losses	(6,000)		(6,000)		(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	4,994,000		4,994,000		10,018,000
Total securities, Gross Unrealized Losses	(6,000)		(6,000)		(21,000)
Obligations of state and political subdivisions [Member]
Available for sale securities amortized cost unrealized losses and fair value [Abstract]
Amortized Cost	94,877,000		94,877,000		96,556,000
Gross Unrealized Gains	6,152,000		6,152,000		4,996,000
Gross Unrealized Losses	(54,000)		(54,000)		(5,000)
Fair Value	100,975,000		100,975,000		101,547,000
Available-for-sale securities, fair value and unrealized loss [Abstract]
Total securities, Less than Twelve Months, Fair Value	3,352,000		3,352,000		1,057,000
Total securities, Less than Twelve Months, Gross Unrealized Losses	(54,000)		(54,000)		(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	3,352,000		3,352,000		1,828,000
Total securities, Gross Unrealized Losses	(54,000)		(54,000)		(5,000)
Corporate obligations [Member]
Available for sale securities amortized cost unrealized losses and fair value [Abstract]
Amortized Cost	10,738,000		10,738,000		8,263,000
Gross Unrealized Gains	477,000		477,000		197,000
Gross Unrealized Losses	0		0		0
Fair Value	11,215,000		11,215,000		8,460,000
Mortgage-backed securities in government sponsored entities [Member]
Available for sale securities amortized cost unrealized losses and fair value [Abstract]
Amortized Cost	57,357,000		57,357,000		36,630,000
Gross Unrealized Gains	2,140,000		2,140,000		2,356,000
Gross Unrealized Losses	(118,000)		(118,000)		(12,000)
Fair Value	59,379,000		59,379,000		38,974,000
Available-for-sale securities, fair value and unrealized loss [Abstract]
Total securities, Less than Twelve Months, Fair Value	6,755,000		6,755,000		3,164,000
Total securities, Less than Twelve Months, Gross Unrealized Losses	(118,000)		(118,000)		(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	6,755,000		6,755,000		3,164,000
Total securities, Gross Unrealized Losses	(118,000)		(118,000)		(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	473,000		473,000		420,000
Gross Unrealized Losses	(11,000)		(11,000)		(1,000)
Fair Value	1,373,000		1,373,000		1,242,000
Available-for-sale securities, fair value and unrealized loss [Abstract]
Total securities, Less than Twelve Months, Fair Value	39,000		39,000		39,000
Total securities, Less than Twelve Months, Gross Unrealized Losses	(11,000)		(11,000)		(1,000)
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	39,000		39,000		39,000
Total securities, Gross Unrealized Losses	$ (11,000)		$ (11,000)		$ (1,000)