Securities (Details) (USD $)	6 Months Ended																		3 Months Ended		12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012	Jun. 30, 2013 U.S. government agencies [Member]	Dec. 31, 2012 U.S. government agencies [Member]	Jun. 30, 2013 Obligations of states and political subdivisions [Member]	Dec. 31, 2012 Obligations of states and political subdivisions [Member]	Jun. 30, 2013 Mortgage-backed securities [Member]	Jun. 30, 2013 Mortgage-backed securities, Agency [Member]	Dec. 31, 2012 Mortgage-backed securities, Agency [Member]	Jun. 30, 2013 Mortgage-backed securities, Non-agency [Member]	Dec. 31, 2012 Mortgage-backed securities, Non-agency [Member]	Jun. 30, 2013 Other asset backed securities [Member]	Dec. 31, 2012 Other asset backed securities [Member]	Jun. 30, 2013 Corporate preferred stock [Member]	Dec. 31, 2012 Corporate preferred stock [Member]	Jun. 30, 2013 Corporate securities [Member]	Dec. 31, 2012 Corporate securities [Member]	Sep. 30, 2012 Trust-preferred securities [Member]	Jun. 30, 2012 Trust-preferred securities [Member]	Dec. 31, 2011 Trust-preferred securities [Member]	Jun. 30, 2013 Trust-preferred securities [Member]
Amortized costs and fair values of securities available for sale [Abstract]
Amortized Cost	$ 316,041,000		$ 309,196,000	$ 13,720,000	$ 15,391,000	$ 79,309,000	$ 74,485,000		$ 162,925,000	$ 161,564,000	$ 17,529,000	$ 15,310,000	$ 32,283,000	$ 33,648,000	$ 68,000	$ 68,000	$ 10,207,000	$ 8,730,000
Gross Unrealized Gains	7,822,000		11,416,000	300,000	459,000	1,921,000	3,920,000		4,592,000	5,659,000	148,000	287,000	839,000	1,079,000	2,000	0	20,000	12,000
Gross Unrealized Losses	(3,731,000)		(1,155,000)	(72,000)	(28,000)	(2,083,000)	(105,000)		(954,000)	(280,000)	(186,000)	(18,000)	(89,000)	(85,000)	0	(6,000)	(347,000)	(633,000)
Fair Value	320,132,000		319,457,000	13,948,000	15,822,000	79,147,000	78,300,000		166,563,000	166,943,000	17,491,000	15,579,000	33,033,000	34,642,000	70,000	62,000	9,880,000	8,109,000
Amortized Cost [Abstract]
Due in one year or less	3,677,000
Due after one year through five years	35,915,000
Due after five years through ten years	24,264,000
Due after ten years	39,380,000
Total	316,041,000							180,454,000					32,283,000		68,000
Fair Value [Abstract]
Due in one year or less	3,708,000
Due after one year through five years	36,686,000
Due after five years through ten years	24,176,000
Due after ten years	38,405,000
Total	320,132,000							184,054,000					33,033,000		70,000
Proceeds from sales of securities	9,900,000
Net gains realized on sale of securities	373,000
Tax expense related to realized gains	127,000
Carrying value of securities pledged for fiduciary powers	120,100,000
Fair Value [Abstract]
Less than Twelve Months	90,695,000		41,246,000	5,521,000	3,850,000	26,468,000	6,966,000		42,803,000	24,344,000	11,087,000	3,295,000	333,000	2,791,000		0	4,483,000	0
Twelve Months or Greater	9,193,000		9,575,000	16,000	16,000	0	0		2,570,000	1,241,000	0	0	2,357,000	1,418,000		33,000	4,250,000	6,867,000
Total	99,888,000		50,821,000	5,537,000	3,866,000	26,468,000	6,966,000		45,373,000	25,585,000	11,087,000	3,295,000	2,690,000	4,209,000		33,000	8,733,000	6,867,000				0
Gross Unrealized Losses [Abstract]
Less than Twelve Months	(3,282,000)		(442,000)	(72,000)	(28,000)	(2,083,000)	(105,000)		(844,000)	(234,000)	(186,000)	(18,000)	0	(57,000)		0	(97,000)	0
Twelve Months or Greater	(449,000)		(713,000)	0	0	0	0		(110,000)	(46,000)	0	0	(89,000)	(28,000)		(6,000)	(250,000)	(633,000)
Total	(3,731,000)		(1,155,000)	(72,000)	(28,000)	(2,083,000)	(105,000)		(954,000)	(280,000)	(186,000)	(18,000)	(89,000)	(85,000)		(6,000)	(347,000)	(633,000)
Gain on securities available for sale																			149,000	142,000
Credit losses recognized in prior period earnings	$ 0	$ 0																	$ 0		$ 2,400,000