Benefit Plan (Components Of Net Periodic Benefit Expense) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Pension plan contributions	$ 0	$ 0
Service cost	2,437	2,479
Interest cost	1,426	1,340
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	(590)	441
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	2,437	2,479
Interest cost	1,426	1,340
Expected return on plan assets	(4,449)	(3,933)
Recognized net actuarial loss	(4)	555
Benefit expense	(590)	441
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	213	204
Interest cost	183	149
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	396	353
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	213	204
Interest cost	183	149
Benefit expense	$ 396	$ 353