Investment Securities (Schedule Of Contractual Maturities Of Investment Securities) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Investment Holdings [Line Items]
Available-for-sale securities, due within one year, amortized cost	$ 11,608
Available-for-sale securities, after one year through five years, amortized cost	250,556
Available-for-sale securities, after five years through ten years, amortized cost	979,600
Available-for-sale securities, after ten years, amortized cost	2,622,591
Available-for-sale securities, amortized cost	3,864,355	$ 2,801,500
Available-for-sale securities, due within one year, fair value	11,749
Available-for-sale securities, after one year through five years, fair value	256,279
Available-for-sale securities, after five years through ten years, fair value	1,004,824
Available-for-sale securities, after ten years, fair value	2,597,583
Available-for-sale securities, fair value	3,870,435	2,932,558
Held-to-maturity securities, due within one year, amortized cost	0
Held-to-maturity securities, After one year through five years, amortized cost	2
Held-to-maturity securities, after five years through ten years, amortized cost	7
Held-to-maturity securities, after ten years, amortized cost	2,735
Held to maturity, at amortized cost	2,744	3,034
Held-to-maturity securities, due within one year, fair value	0
Held-to-maturity securities, after one year through five years, fair value	2
Held-to-maturity securities, after five years through ten years, fair value	7
Held-to-maturity securities, after ten years, fair value	3,505
Held-to-maturity securities, fair value	$ 3,514	$ 3,883