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		Mar. 31, 2023		Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Available-for-sale Securities, debt maturities, within one year, Amortized Cost		$ 19,821		$ 16,047
Available-for-sale Securities, debt maturities, after one year through three years, Amortized Cost		190,260		185,012
Available-for-sale Securities, debt maturities, after three year through five years, Amortized Cost		104,158		123,696
Available-for-sale Securities, debt maturities, after five year through ten years, Amortized Cost		440,663		442,055
Available-for-sale Securities, debt maturities, after ten years, Amortized Cost		1,066,177		1,096,409
Available-for-sale Securities, Amortized cost		1,821,079		1,863,219
Available-for-sale Securities, debt maturities, within one year, Fair Value		19,301	[1]	15,877
Available-for-sale Securities, debt maturities, after one year through three years, Fair Value		182,257		178,776
Available-for-sale Securities, debt maturities, after three year through five years, Fair Value		92,269		108,707
Available-for-sale Securities, debt maturities, after five year through ten years, fair value		383,638	[1]	380,362
Availably-for-sale Securities, debt maturities, after ten years, Fair Value		946,993	[1]	952,319
Available-for-sale Securities, debt maturities, Fair Value		1,624,458		1,636,041
Held-to-maturity Securities, debt maturities, after five through ten years, Amortized Cost		2,495,221		2,413,239
Held-to-maturity Securities, debt maturities, after ten years, Amortized Cost		3,489,601		3,577,212
Held-to-maturity Securities, Amortized cost	[2]	5,984,822		5,990,451
Held-to-maturity Securities, debt maturities, after five through ten years, Fair Value		2,421,698		2,323,608
Held-to-maturity Securities, debt maturities, after ten years, Fair Value		3,357,847		3,414,810
Held-to-maturity Securities, debt maturities, Fair Value	[2]	$ 5,779,545		$ 5,738,418

[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.