Investment Securities HTM Gross Unrealized Losses (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAbstract
Unrealized losses on held to maturity securities, less than 12 months	$ (55)	$ (5,339)
Unrealized losses on held to maturity securities, 12 months or more	(879)	(383)
Total unrealized losses on held to maturity securities	(934)	(5,722)
Fair value of unrealized losses on held to maturity securities, less than 12 months	14,443	124,435
Fair value of unrealized losses on held to maturity securities, 12 months or more	55,522	5,010
Total fair value of unrealized losses on held to maturity securities	69,965	129,445
Obligations of state and political subdivisions (municipal securities) [Member]
HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAbstract
Unrealized losses on held to maturity securities, less than 12 months	(55)	(5,339)
Unrealized losses on held to maturity securities, 12 months or more	(879)	(383)
Total unrealized losses on held to maturity securities	(934)	(5,722)
Fair value of unrealized losses on held to maturity securities, less than 12 months	14,443	124,435
Fair value of unrealized losses on held to maturity securities, 12 months or more	55,522	5,010
Total fair value of unrealized losses on held to maturity securities	$ 69,965	$ 129,445
Obligations of state and political subdivisions (municipal securities) [Member] | Held To Maturity Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions Less Than One Year [Member]
HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAbstract
Number of held to maturity securities in a continuous unrealized loss position less than twelve months	39	298
Obligations of state and political subdivisions (municipal securities) [Member] | Held To Maturity Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions Greater Than Or Equal To One Year [Member]
HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAbstract
Number of held to maturity securities in a continuous unrealized loss position less than twelve months	119	10