Derivative Instruments (Schedule Of Notional Amounts Of Derivative Instruments) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Derivative [Line Items]
Derivative, Notional Amount	$ 2,890,598	$ 3,015,189
Interest rate swaps
Derivative [Line Items]
Derivative, Notional Amount	2,236,974	2,367,017
Interest rate caps
Derivative [Line Items]
Derivative, Notional Amount	185,177	103,028
Credit risk participation agreements
Derivative [Line Items]
Derivative, Notional Amount	372,661	381,170
Foreign exchange contracts
Derivative [Line Items]
Derivative, Notional Amount	7,566	7,431
Mortgage loan commitments
Derivative [Line Items]
Derivative, Notional Amount	44,233	67,543
Mortgage loan forward sale contracts
Derivative [Line Items]
Derivative, Notional Amount	6,987	0
Forward TBA contracts
Derivative [Line Items]
Derivative, Notional Amount	$ 37,000	$ 89,000