Available-for-Sale and Held-to-Maturity Securities (Schedule Of Gross Unrealized Losses And The Estimated Fair Value By Length Of Time In A Loss Position) (Details) $ in Thousands	Mar. 31, 2022 USD ($)
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	$ (85,089)
Available-for-sale Securities, Estimated fair value, Less than 12 months	1,284,479
Available-for-sale Securities, Gross unrealized losses, 12 months or more	(15,957)
Available-for-sale Securities, Estimated fair value, 12 months or more	183,908
Available-for-sale Securities, Gross unrealized losses, Total	(101,046)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	1,468,387
U.S. Government Agency Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(90)
Available-for-sale Securities, Estimated fair value, Less than 12 months	1,820
Available-for-sale Securities, Gross unrealized losses, 12 months or more	0
Available-for-sale Securities, Estimated fair value, 12 months or more	0
Available-for-sale Securities, Gross unrealized losses, Total	(90)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	1,820
Corporate Fixed Income Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(36,149)
Available-for-sale Securities, Estimated fair value, Less than 12 months	398,824
Available-for-sale Securities, Gross unrealized losses, 12 months or more	0
Available-for-sale Securities, Estimated fair value, 12 months or more	0
Available-for-sale Securities, Gross unrealized losses, Total	(36,149)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	398,824
Mortgage-Backed Securities [Member] \| Agency Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(40,093)
Available-for-sale Securities, Estimated fair value, Less than 12 months	679,722
Available-for-sale Securities, Gross unrealized losses, 12 months or more	(15,257)
Available-for-sale Securities, Estimated fair value, 12 months or more	149,962
Available-for-sale Securities, Gross unrealized losses, Total	(55,350)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	829,684
Mortgage-Backed Securities [Member] \| Commercial [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(2,569)
Available-for-sale Securities, Estimated fair value, Less than 12 months	69,841
Available-for-sale Securities, Gross unrealized losses, 12 months or more	0
Available-for-sale Securities, Estimated fair value, 12 months or more	0
Available-for-sale Securities, Gross unrealized losses, Total	(2,569)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	69,841
Asset-Backed Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(6,188)
Available-for-sale Securities, Estimated fair value, Less than 12 months	134,272
Available-for-sale Securities, Gross unrealized losses, 12 months or more	(700)
Available-for-sale Securities, Estimated fair value, 12 months or more	33,946
Available-for-sale Securities, Gross unrealized losses, Total	(6,888)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	$ 168,218

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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