Guarantees (Details) (USD $)	Mar. 31, 2014 Y	Dec. 31, 2013
Guarantor Obligations [Line Items]
RPA's, minimum in years	3
RPA's, maximum in years	10
Notional amount of underlying interest rate swaps associated with risk participation agreements	$ 797,474,000	$ 740,332,000
Financial Standby Letter Of Credit [Member]
Guarantor Obligations [Line Items]
Guarantor obligations, net liability	3,500,000
Guaranteed maximum potential future payments	333,300,000
Risk Participation Agreement [Member] | Indirect Guarantee Of Indebtedness [Member]
Guarantor Obligations [Line Items]
Notional amount of underlying interest rate swaps associated with risk participation agreements	65,400,000
Not Designated as Hedging Instrument [Member] | Risk Participation Agreement [Member] | Indirect Guarantee Of Indebtedness [Member]
Guarantor Obligations [Line Items]
Derivative Liabilities	$ (71,000)