Investment Securities (Schedule Of Contractual Maturities Of Investment Securities) (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Investment Holdings [Line Items]
Available-for-sale securities, due within one year, amortized cost	$ 9,861
Available-for-sale securities, after one year through five years, amortized cost	417,691
Available-for-sale securities, after five years through ten years, amortized cost	866,834
Available-for-sale securities, after ten years, amortized cost	2,505,688
Available-for-sale securities, amortized cost	3,800,074	$ 3,864,355
Available-for-sale securities, due within one year, fair value	9,865
Available-for-sale securities, after one year through five years, fair value	402,577
Available-for-sale securities, after five years through ten years, fair value	799,668
Available-for-sale securities, after ten years, fair value	2,204,597
Debt Securities, Available-for-sale	3,416,707	3,870,435
Held-to-maturity securities, due within one year, amortized cost	0
Held-to-maturity securities, after one year through five years, amortized cost	4
Held-to-maturity securities, after five years through ten years, amortized cost	3
Held-to-maturity securities, after ten years, amortized cost	2,630
Investment securities held to maturity	2,637	2,744
Held-to-maturity securities, due within one year, fair value	0
Held-to-maturity securities, after one year through five years, fair value	4
Held-to-maturity securities, after five years through ten years, fair value	3
Held-to-maturity securities, after ten years, fair value	3,378
Held-to-maturity securities, fair value	$ 3,385	$ 3,514