Investment Securities (Schedule Of Contractual Maturities Of Investment Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Debt and Equity Securities, FV-NI [Line Items]
Available-for-sale securities, due within one year, amortized cost	$ 26,219
Available-for-sale securities, after one year through five years, amortized cost	1,974,579
Available-for-sale securities, after five years through ten years, amortized cost	2,591,611
Available-for-sale securities, after ten years, amortized cost	4,787,994
Available-for-sale securities, amortized cost	9,380,403	$ 3,738,281
Available-for-sale securities, due within one year, fair value	26,100
Available-for-sale securities, after one year through five years, fair value	1,909,880
Available-for-sale securities, after five years through ten years, fair value	2,406,645
Available-for-sale securities, after ten years, fair value	4,161,361
Debt Securities, Available-for-sale	8,503,986	3,196,166
Held-to-maturity securities, due within one year, amortized cost	0
Held-to-maturity securities, after one year through five years, amortized cost	3
Held-to-maturity securities, after five years through ten years, amortized cost	3
Held-to-maturity securities, after ten years, amortized cost	2,338
Investment securities held to maturity	2,344	2,476
Held-to-maturity securities, due within one year, fair value	0
Held-to-maturity securities, after one year through five years, fair value	3
Held-to-maturity securities, after five years through ten years, fair value	13
Held-to-maturity securities, after ten years, fair value	3,042
Held-to-maturity securities, fair value	$ 3,058	$ 3,197