Securities (Details 2) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Available for sale securities continuous unrealized loss position fair value and unrealized losses
Securities with unrealized losses,12 months or longer, Fair Value	$ 16,117	$ 27,282
Total temporarily impaired securities, Less than 12 Months Fair Value	173,322	111,328
Total Temporarily Impaired Securities, 12 months or longer, Fair Value	189,439	138,610
Total Temporarily Impaired Securities Continuous Unrealized Losses Position Less than 12 Months Unrealized Losses	(1,121)	(2,490)
Total Temporarily Impaired Securities Continuous Unrealized Losses Position Twelve Months or Longer Unrealized Losses	(191)	(1,486)
Total Temporarily Impaired Securities Continuous Unrealized Losses Position Unrealized Losses	(1,312)	(3,976)
Mortgage-backed securities of U.S Government Sponsored Entities [Member]
Available for sale securities continuous unrealized loss position fair value and unrealized losses
Less than Twelve Months, Fair Value	23,096	18,800
Less than 12 Months, Aggregate Losses	(86)	(37)
Twelve Months or Longer, Fair Value	0	0
12 Months or Longer, Aggregate Losses	0	0
Fair Value, Total	23,096	18,800
Aggregate Losses	(86)	(37)
Collateralized mortgage obligations of U.S. Government Sponsored Entities [Member]
Available for sale securities continuous unrealized loss position fair value and unrealized losses
Less than Twelve Months, Fair Value	149,926
Twelve Months or Longer, Fair Value	5,886	0
12 Months or Longer, Aggregate Losses	(105)	0
Available for Sale and Held to Maturity Securities Continuous Unrealized Loss Position Aggregate Losses	(1,134)	(452)
Securities with unrealized losses,12 months or longer, Fair Value	155,812	59,913
Securities with unrealized losses, Less than 12 months, Fair Value		59,913
Available for Sale and Held to Maturity Securities Continuous Unrealized Loss Position Less than 12 Months Aggregate Losses	(1,029)	(452)
Private collateralized mortgage obligations [Member]
Available for sale securities continuous unrealized loss position fair value and unrealized losses
Less than Twelve Months, Fair Value	0	32,615
Less than 12 Months, Aggregate Losses	0	(2,001)
Twelve Months or Longer, Fair Value	10,106	27,282
12 Months or Longer, Aggregate Losses	(84)	(1,486)
Fair Value, Total	10,106	59,897
Aggregate Losses	(84)	(3,487)
Total Temporarily Impaired Securities Continuous Unrealized Losses Position Unrealized Losses	(1,300)
Obligations of state and political subdivisions [Member]
Available for sale securities continuous unrealized loss position fair value and unrealized losses
Less than Twelve Months, Fair Value	300
Less than 12 Months, Aggregate Losses	(6)
Twelve Months or Longer, Fair Value	125
12 Months or Longer, Aggregate Losses	(2)
Fair Value, Total	425
Aggregate Losses	$ (8)