Available-For-Sale And Held-To-Maturity Securities (Schedule Of Amortized Cost And Fair Values Of Debt Securities By Contractual Maturity) (Details) - USD ($) $ in Thousands	Dec. 31, 2021		Dec. 31, 2020
Investments Debt And Equity Securities [Abstract]
Available-for-sale Securities, debt maturities, within one year, Amortized Cost	$ 36,671		$ 143,462
Available-for-sale Securities, debt maturities, after one year through three years, Amortized Cost	217,606		134,040
Available-for-sale Securities, debt maturities, after three year through five years, Amortized Cost	192,271		247,907
Available-for-sale Securities, debt maturities, after five year through ten years, Amortized Cost	455,429		429,921
Available-for-sale Securities, debt maturities, after ten years, Amortized Cost	1,202,536		1,229,009
Available-for-sale Securities, Amortized cost	2,104,513		2,184,339
Available-for-sale Securities, debt maturities, within one year, Fair Value	36,899	[1]	144,362
Available-for-sale Securities, debt maturities, after one year through three years, Fair Value	222,942		137,625
Available-for-sale Securities, debt maturities, after three year through five years, Fair Value	196,380		266,139
Available-for-sale Securities, debt maturities, after five year through ten years, fair value	455,848	[1]	435,111
Availably-for-sale Securities, debt maturities, after ten years, Fair Value	1,201,824	[1]	1,247,060
Available-for-sale Securities, debt maturities, Fair Value	2,113,893	[1]	2,230,297
Held-to-maturity Securities, debt maturities, after three through five years, Amortized Cost	2,825		17,460
Held-to-maturity Securities, debt maturities, after five through ten years, Amortized Cost	2,282,162		1,932,439
Held-to-maturity Securities, debt maturities, after ten years, Amortized Cost	3,063,571		2,167,485
Held-to-maturity Securities, Amortized cost	5,348,558	[2]	4,117,384
Held-to-maturity Securities, debt maturities, after three through five years, Fair Value	2,825		17,460
Held-to-maturity Securities, debt maturities, after five through ten years, Fair Value	2,278,597		1,926,425
Held-to-maturity Securities, debt maturities, after ten years, Fair Value	3,062,059		2,164,075
Held-to-maturity Securities, debt maturities, Fair Value	$ 5,343,481	[2]	$ 4,107,960

[1] Due to the immaterial amount of income recognized on tax-exempt securities, yields were not calculated on a tax-equivalent basis.

[2] Held-to-maturity securities are carried in the consolidated statements of financial condition at amortized cost, and the changes in the value of these securities, other than impairment charges, are not reported on the consolidated financial statements.