Investment Securities (Details 2) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Fair Value
Less than 12 Months	$ 272,203,000	$ 51,410,000
12 months or Longer	18,831,000	7,860,000
Total	291,034,000	59,270,000
Unrealized Losses
Less than 12 Months	(6,182,000)	(153,000)
12 months or Longer	(454,000)	(535,000)
Total	(6,636,000)	(688,000)
Investment securities pledged as collateral	236,580,000	216,340,000
U.S. Treasury and Federal agencies securities
Fair Value
Less than 12 Months	139,539,000	37,316,000
12 months or Longer	15,094,000
Total	154,633,000	37,316,000
Unrealized Losses
Less than 12 Months	(3,337,000)	(83,000)
12 months or Longer	(131,000)
Total	(3,468,000)	(83,000)
U.S. States and political subdivisions securities
Fair Value
Less than 12 Months	30,490,000	7,730,000
12 months or Longer	2,691,000	3,364,000
Total	33,181,000	11,094,000
Unrealized Losses
Less than 12 Months	(671,000)	(46,000)
12 months or Longer	(313,000)	(436,000)
Total	(984,000)	(482,000)
Mortgage-backed securities - Federal agencies
Fair Value
Less than 12 Months	94,174,000	6,264,000
12 months or Longer	49,000	60,000
Total	94,223,000	6,324,000
Unrealized Losses
Less than 12 Months	(2,171,000)	(24,000)
12 months or Longer	(1,000)	(1,000)
Total	(2,172,000)	(25,000)
Corporate debt securities
Fair Value
Less than 12 Months	7,900,000
12 months or Longer	993,000	4,431,000
Total	8,893,000	4,431,000
Unrealized Losses
Less than 12 Months	(3,000)
12 months or Longer	(6,000)	(94,000)
Total	(9,000)	(94,000)
Foreign government and other securities
Fair Value
Less than 12 Months	100,000	100,000
Total	100,000	100,000
Total debt securities
Fair Value
Less than 12 Months	272,203,000	51,410,000
12 months or Longer	18,827,000	7,855,000
Total	291,030,000	59,265,000
Unrealized Losses
Less than 12 Months	(6,182,000)	(153,000)
12 months or Longer	(451,000)	(531,000)
Total	(6,633,000)	(684,000)
Marketable equity securities
Fair Value
12 months or Longer	4,000	5,000
Total	4,000	5,000
Unrealized Losses
12 months or Longer	(3,000)	(4,000)
Total	$ (3,000)	$ (4,000)