Derivative Instruments (Schedule Of Notional Amounts Of Derivative Instruments) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Derivative [Line Items]
Derivative, Notional Amount	$ 4,607,919	$ 4,525,856
Interest Rate Swaps [Member]
Derivative [Line Items]
Derivative, Notional Amount	2,491,862	2,606,181
Interest Rate Floor [Member]
Derivative [Line Items]
Derivative, Notional Amount	1,500,000	1,500,000
Interest Rate Caps [Member]
Derivative [Line Items]
Derivative, Notional Amount	126,892	59,316
Credit Risk Participation Agreements [Member]
Derivative [Line Items]
Derivative, Notional Amount	387,404	316,225
Foreign Exchange Contracts [Member]
Derivative [Line Items]
Derivative, Notional Amount	7,359	10,936
Mortgage Loan Commitments [Member]
Derivative [Line Items]
Derivative, Notional Amount	50,824	13,755
Mortgage Loan Forward Sale Contracts [Member]
Derivative [Line Items]
Derivative, Notional Amount	578	1,943
Forward TBA Contracts [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 43,000	$ 17,500