Available-For-Sale And Held-To-Maturity Securities (Schedule Of Amortized Cost And Fair Values Of The Available For Sale Securities And Held To Maturity Securities) (Details) - USD ($) $ in Thousands		Jun. 30, 2023		Dec. 31, 2022
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Amortized cost		$ 1,797,456		$ 1,863,219
Available for sale securities, unrealized gains	[1]	38		151
Available-for-sale Securities, Gross unrealized losses	[1]	(215,076)		(227,329)
Available-for-sale securities		1,582,418		1,636,041
Held-to-maturity Securities, Amortized cost	[2]	5,951,482		5,990,451
Held-to-maturity Securities, Gross unrealized gains	[1],[2]	3,793		3,213
Held-to-maturity Securities, Gross unrealized losses	[1],[2]	(165,487)		(255,246)
Held-to-maturity securities, Estimated fair value	[2]	5,789,788		5,738,418
U.S. Government Agency Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Amortized cost		2,360		2,345
Available for sale securities, unrealized gains	[1]	2		6
Available-for-sale Securities, Gross unrealized losses	[1]	(199)		(203)
Available-for-sale securities		2,163		2,148
State And Municipal Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Amortized cost		2,350		2,350
Available for sale securities, unrealized gains	[1]	0		1
Available-for-sale Securities, Gross unrealized losses	[1]	0		0
Available-for-sale securities		2,350		2,351
Agency Mortgage-Backed Securities [Member] | Agency Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Amortized cost		897,921		921,676
Available for sale securities, unrealized gains	[1]	0		0
Available-for-sale Securities, Gross unrealized losses	[1]	(129,373)		(130,654)
Available-for-sale securities		768,548	[3]	791,022
Agency Mortgage-Backed Securities [Member] | Commercial [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Amortized cost		70,886		71,462
Available for sale securities, unrealized gains	[1]	0		0
Available-for-sale Securities, Gross unrealized losses	[1]	(5,308)		(5,349)
Available-for-sale securities		65,578	[3]	66,113
Agency Mortgage-Backed Securities [Member] | Non-Agency [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Amortized cost		368		442
Available for sale securities, unrealized gains	[1]	0		0
Available-for-sale Securities, Gross unrealized losses	[1]	(25)		(54)
Available-for-sale securities		343	[3]	388
Corporate Fixed Income Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Amortized cost		622,129		643,379
Available for sale securities, unrealized gains	[1]	10		18
Available-for-sale Securities, Gross unrealized losses	[1]	(76,175)		(77,103)
Available-for-sale securities		545,964		566,294
Asset-Backed Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Amortized cost		201,442		221,565
Available for sale securities, unrealized gains	[1]	26		126
Available-for-sale Securities, Gross unrealized losses	[1]	(3,996)		(13,966)
Available-for-sale securities		197,472	[3]	$ 207,725
Held-to-maturity Securities, Amortized cost		$ 5,951,482

[1] Unrealized gains/(losses) related to available-for-sale securities are reported in accumulated other comprehensive income.

[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.

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