Derivative Instruments (Impact Of Derivatives On Balance Sheet) (Details) - Not Designated As Hedging Instruments - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Assets
Derivative [Line Items]
Fair Value of Derivative Assets	$ 11,722	$ 20,623
Other Assets | Interest rate contracts
Derivative [Line Items]
Fair Value of Derivative Assets	10,786	17,157
Other Assets | Mortgage derivatives
Derivative [Line Items]
Fair Value of Derivative Assets	936	3,466
Other Assets | Visa Derivative
Derivative [Line Items]
Fair Value of Derivative Assets	0	0
Other Liabilities
Derivative [Line Items]
Fair Value of Derivative Liabilities	17,097	23,299
Other Liabilities | Interest rate contracts
Derivative [Line Items]
Fair Value of Derivative Liabilities	12,638	17,531
Other Liabilities | Mortgage derivatives
Derivative [Line Items]
Fair Value of Derivative Liabilities	129	0
Other Liabilities | Visa Derivative
Derivative [Line Items]
Fair Value of Derivative Liabilities	$ 4,330	$ 5,768