Guarantees (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Guarantor Obligations [Line Items]
Derivative Liabilities	(13,782,000)	$ (10,948,000)
Notional amount of underlying interest rate swaps associated with risk participation agreements	924,884,000	797,030,000
Financial Standby Letter Of Credit [Member]
Guarantor Obligations [Line Items]
Standby letters of credit, net liability	3,100,000
Contractual amount of letters of credit, guaranteed maximum potential future payments	313,800,000
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	68,900,000
Not Designated as Hedging Instrument [Member] | Risk Participation Agreement [Member] | Indirect Guarantee Of Indebtedness [Member]
Guarantor Obligations [Line Items]
Derivative Liabilities	(253,000)
Minimum [Member] | Risk Participation Agreement [Member]
Guarantor Obligations [Line Items]
Term, in years	3 years
Maximum [Member] | Risk Participation Agreement [Member]
Guarantor Obligations [Line Items]
Term, in years	11 years