Benefit Plan (Components Of Net Periodic Benefit Expense) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Pension plan contributions	$ 0	$ 0
Service cost	1,559,000	2,437,000
Interest cost	1,631,000	1,426,000
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	(334,000)	(590,000)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	1,559,000	2,437,000
Interest cost	1,631,000	1,426,000
Expected return on plan assets	(3,536,000)	(4,449,000)
Recognized net actuarial loss	12,000	(4,000)
Benefit expense	(334,000)	(590,000)
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	234,000	213,000
Interest cost	176,000	183,000
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	410,000	396,000
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	234,000	213,000
Interest cost	176,000	183,000
Benefit expense	$ 410,000	$ 396,000