Securities (Details) (USD $)	12 Months Ended																	3 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 U.S. Government Agencies [Member]	Dec. 31, 2011 U.S. Government Agencies [Member]	Dec. 31, 2012 Obligations of States and Political Subdivisions [Member]	Dec. 31, 2011 Obligations of States and Political Subdivisions [Member]	Dec. 31, 2012 Mortgage-backed Securities, Agency [Member]	Dec. 31, 2011 Mortgage-backed Securities, Agency [Member]	Dec. 31, 2012 Mortgage-backed Securities, Non-agency [Member]	Dec. 31, 2011 Mortgage-backed Securities, Non-agency [Member]	Dec. 31, 2012 Other Asset Backed Securities [Member]	Dec. 31, 2011 Other Asset Backed Securities [Member]	Dec. 31, 2012 Corporate Preferred Stock [Member]	Dec. 31, 2011 Corporate Preferred Stock [Member]	Dec. 31, 2012 Corporate Securities [Member]	Dec. 31, 2011 Corporate Securities [Member]	Sep. 30, 2012 Trust-Preferred Securities [Member]	Jun. 30, 2012 Trust-Preferred Securities [Member]	Dec. 31, 2011 Trust-Preferred Securities [Member]	Dec. 31, 2012 Mortgage-backed securities [Member]
Amortized costs and fair values of securities available for sale [Abstract]
Amortized Cost	$ 309,196,000	$ 301,979,000		$ 15,391,000	$ 9,068,000	$ 74,485,000	$ 65,090,000	$ 161,564,000	$ 181,797,000	$ 15,310,000	$ 18,737,000	$ 33,648,000	$ 16,110,000	$ 68,000	$ 68,000	$ 8,730,000	$ 10,612,000			$ 497,000
Gross Unrealized Gains	11,416,000	8,440,000		459,000	293,000	3,920,000	2,503,000	5,659,000	5,482,000	287,000	67,000	1,079,000	90,000	0	0	12,000	5,000			0
Gross Unrealized Losses	(1,155,000)	(2,177,000)		(28,000)	(18,000)	(105,000)	(51,000)	(280,000)	(209,000)	(18,000)	(598,000)	(85,000)	(404,000)	(6,000)	(28,000)	(633,000)	(641,000)			(228,000)
Fair Value	319,457,000	308,242,000		15,822,000	9,343,000	78,300,000	67,542,000	166,943,000	187,070,000	15,579,000	18,206,000	34,642,000	15,796,000	62,000	40,000	8,109,000	9,976,000			269,000
Amortized Cost [Abstract]
Due in one year or less	4,049,000
Due after one year through five years	26,597,000
Due after five years through ten years	33,651,000
Due after ten years	34,309,000
Total	309,196,000											33,648,000		68,000							176,874,000
Fair Value [Abstract]
Due in one year or less	4,101,000
Due after one year through five years	26,890,000
Due after five years through ten years	35,603,000
Due after ten years	35,637,000
Total	319,457,000											34,642,000		62,000							182,522,000
Proceeds from sales of securities	41,000,000	37,600,000	68,800,000
Gross gains realized on sale of securities	743,000	476,000	1,300,000
Gross loss realized on sale of securities	298,000	16,000	457,000
Net impairment losses	0	25,000	1,103,000
Tax expense related to realized gains	151,000	148,000	(81,000)
Carrying value of securities pledged for fiduciary powers	142,200,000	116,200,000
Fair Value [Abstract]
Less than Twelve Months	41,246,000	47,976,000		3,850,000	2,045,000	6,966,000	43,000	24,344,000	22,768,000	3,295,000	4,773,000	2,791,000	10,572,000	0	0	0	7,775,000
Twelve Months or Greater	9,575,000	10,595,000		16,000	26,000	0	2,243,000	1,241,000	0	0	4,522,000	1,418,000	1,467,000	33,000	11,000	6,867,000	2,057,000
Total	50,821,000	58,571,000		3,866,000	2,071,000	6,966,000	2,286,000	25,585,000	22,768,000	3,295,000	9,295,000	4,209,000	12,039,000	33,000	11,000	6,867,000	9,832,000
Gross Unrealized Losses [Abstract]
Less than Twelve Months	(442,000)	(919,000)		(28,000)	(18,000)	(105,000)	0	(234,000)	(209,000)	(18,000)	(103,000)	(57,000)	(362,000)	0	0	0	(227,000)
Twelve Months or Greater	(713,000)	(1,258,000)		0	0	0	(51,000)	(46,000)	0	0	(495,000)	(28,000)	(42,000)	(6,000)	(28,000)	(633,000)	(414,000)
Total	(1,155,000)	(2,177,000)		(28,000)	(18,000)	(105,000)	(51,000)	(280,000)	(209,000)	(18,000)	(598,000)	(85,000)	(404,000)	(6,000)	(28,000)	(633,000)	(641,000)
Loss on securities sold																		149,000	142,000
Credit losses recognized in prior period earnings		$ 25,000																		$ 2,400,000