Investments In Securities and Fair Value (Schedule Of Unrealized Losses On Investments) (Details) $ in Thousands	Sep. 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	98	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	(6)	(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	(6)	(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	9,094	3,221
Total temporarily impaired securities, Less than 12 Months, Unrealized Losses	(256)	(36)
Total temporarily impaired securities, 12 Months or Longer, Fair Value	98	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(4)	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	9,192	3,221
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(260)	(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	15,800	12,568
Total temporarily impaired securities, Less than 12 Months, Unrealized Losses	(263)	(216)
Total temporarily impaired securities, 12 Months or Longer, Fair Value	4,385	1,100
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(264)	(3)
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	20,185	13,668
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(527)	(219)
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Total temporarily impaired securities, Less than 12 Months, Fair Value	18,677	6,498
Total temporarily impaired securities, Less than 12 Months, Unrealized Losses	(577)	(68)
Total temporarily impaired securities, 12 Months or Longer, Fair Value	491	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(9)	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	19,168	6,498
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(586)	(68)
Total temporarily impaired securities
Debt Securities, Available-for-sale [Line Items]
Total temporarily impaired securities, Less than 12 Months, Fair Value	43,573	26,609
Total temporarily impaired securities, Less than 12 Months, Unrealized Losses	(1,102)	(327)
Total temporarily impaired securities, 12 Months or Longer, Fair Value	4,974	1,100
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(277)	(3)
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	48,547	27,709
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ (1,379)	$ (330)