Investments In Securities and Fair Value (Schedule Of Unrealized Losses On Investments) (Details) $ in Thousands	Jun. 30, 2023 USD ($) segment	Dec. 31, 2022 USD ($) segment
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | segment	83	51
Government obligations
Debt Securities, Available-for-sale [Line Items]
Total temporarily impaired securities, Less than 12 Months, Fair Value	$ 2	$ 4,322
Total temporarily impaired securities, Less than 12 Months, Unrealized Losses	(8)	(7)
Total temporarily impaired securities, 12 Months or Longer, Fair Value	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	2	4,322
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(8)	(7)
General obligations of U.S. states, territories and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Total temporarily impaired securities, Less than 12 Months, Fair Value	6,939	3,221
Total temporarily impaired securities, Less than 12 Months, Unrealized Losses	(69)	(36)
Total temporarily impaired securities, 12 Months or Longer, Fair Value	101	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(2)	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	7,040	3,221
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(71)	(36)
Special revenue issuer obligations of U.S. states, territories and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Total temporarily impaired securities, Less than 12 Months, Fair Value	7,196	12,568
Total temporarily impaired securities, Less than 12 Months, Unrealized Losses	(48)	(216)
Total temporarily impaired securities, 12 Months or Longer, Fair Value	3,893	1,100
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(72)	(3)
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	11,089	13,668
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(120)	(219)
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Total temporarily impaired securities, Less than 12 Months, Fair Value	15,126	6,498
Total temporarily impaired securities, Less than 12 Months, Unrealized Losses	(187)	(68)
Total temporarily impaired securities, 12 Months or Longer, Fair Value	248	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(3)	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	15,374	6,498
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(190)	(68)
Total temporarily impaired securities
Debt Securities, Available-for-sale [Line Items]
Total temporarily impaired securities, Less than 12 Months, Fair Value	29,263	26,609
Total temporarily impaired securities, Less than 12 Months, Unrealized Losses	(312)	(327)
Total temporarily impaired securities, 12 Months or Longer, Fair Value	4,242	1,100
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(77)	(3)
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	33,505	27,709
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ (389)	$ (330)