Derivative Instruments (Schedule Of Notional Amounts Of Derivative Instruments) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Derivative [Line Items]
Notional Amount of Derivatives	$ 1,923,619	$ 1,904,093
Interest Rate Swaps [Member]
Derivative [Line Items]
Notional Amount of Derivatives	1,693,637	1,685,099
Interest Rate Caps [Member]
Derivative [Line Items]
Notional Amount of Derivatives	32,890	59,379
Credit Risk Participation Agreements [Member]
Derivative [Line Items]
Notional Amount of Derivatives	118,081	121,514
Foreign Exchange Contracts [Member]
Derivative [Line Items]
Notional Amount of Derivatives	5,556	4,046
Mortgage Loan Commitments [Member]
Derivative [Line Items]
Notional Amount of Derivatives	29,429	12,429
Mortgage Loan Forward Sale Contracts [Member]
Derivative [Line Items]
Notional Amount of Derivatives	1,026	6,626
Forward TBA Contracts [Member]
Derivative [Line Items]
Notional Amount of Derivatives	$ 43,000	$ 15,000