Guarantees (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Guarantor Obligations [Line Items]
Derivative Liabilities	$ (16,251)	$ (10,948)
Notional amount of underlying interest rate swaps associated with risk participation agreements	1,062,402	$ 797,030
Financial Standby Letter Of Credit [Member]
Guarantor Obligations [Line Items]
Standby letters of credit, net liability	2,600
Contractual amount of letters of credit, guaranteed maximum potential future payments	335,000
Risk Participation Agreement [Member] | Indirect Guarantee Of Indebtedness [Member]
Guarantor Obligations [Line Items]
Derivative Liabilities	(234)
Notional amount of underlying interest rate swaps associated with risk participation agreements	$ 66,800
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