Derivative Instruments (Schedule Of Notional Amounts Of Derivative Instruments) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Derivative, Notional Amount	$ 3,254,921	$ 1,963,178
Interest Rate Swaps [Member]
Derivative [Line Items]
Derivative, Notional Amount	2,006,280	1,741,412
Interest Rate Floor [Member]
Derivative [Line Items]
Derivative, Notional Amount	1,000,000	0
Interest Rate Caps [Member]
Derivative [Line Items]
Derivative, Notional Amount	62,163	31,776
Credit Risk Participation Agreements [Member]
Derivative [Line Items]
Derivative, Notional Amount	143,460	133,488
Foreign Exchange Contracts [Member]
Derivative [Line Items]
Derivative, Notional Amount	6,206	11,826
Mortgage Loan Commitments [Member]
Derivative [Line Items]
Derivative, Notional Amount	14,544	17,110
Mortgage Loan Forward Sale Contracts [Member]
Derivative [Line Items]
Derivative, Notional Amount	5,768	2,566
Forward TBA Contracts [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 16,500	$ 25,000