Derivative Instruments (Schedule Of Notional Amounts Of Derivative Instruments) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Notional Amount of Derivatives	$ 1,887,981	$ 1,904,093
Interest Rate Swaps [Member]
Derivative [Line Items]
Notional Amount of Derivatives	1,684,818	1,685,099
Interest Rate Caps [Member]
Derivative [Line Items]
Notional Amount of Derivatives	33,036	59,379
Credit Risk Participation Agreements [Member]
Derivative [Line Items]
Notional Amount of Derivatives	118,341	121,514
Foreign Exchange Contracts [Member]
Derivative [Line Items]
Notional Amount of Derivatives	1,574	4,046
Mortgage Loan Commitments [Member]
Derivative [Line Items]
Notional Amount of Derivatives	22,378	12,429
Mortgage Loan Forward Sale Contracts [Member]
Derivative [Line Items]
Notional Amount of Derivatives	1,834	6,626
Forward TBA Contracts [Member]
Derivative [Line Items]
Notional Amount of Derivatives	$ 26,000	$ 15,000