Derivative Instruments (Schedule Of Notional Amounts Of Derivative Instruments) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Derivative [Line Items]
Derivative, Notional Amount	$ 3,548,498	$ 4,525,856
Interest Rate Swaps [Member]
Derivative [Line Items]
Derivative, Notional Amount	2,425,837	2,606,181
Interest Rate Floor [Member]
Derivative [Line Items]
Derivative, Notional Amount	500,000	1,500,000
Interest Rate Caps [Member]
Derivative [Line Items]
Derivative, Notional Amount	113,495	59,316
Credit Risk Participation Agreements [Member]
Derivative [Line Items]
Derivative, Notional Amount	365,611	316,225
Foreign Exchange Contracts [Member]
Derivative [Line Items]
Derivative, Notional Amount	9,293	10,936
Mortgage Loan Commitments [Member]
Derivative [Line Items]
Derivative, Notional Amount	60,311	13,755
Mortgage Loan Forward Sale Contracts [Member]
Derivative [Line Items]
Derivative, Notional Amount	9,451	1,943
Forward TBA Contracts [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 64,500	$ 17,500