Employee Pension Plans (Summary Of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Summary of net periodic benefit cost
Interest cost	$ 582	$ 758
Service cost	236	231
Expected return on plan assets	(1,015)	(1,006)
Recognized net actuarial losses	683	592
Net periodic benefit cost	$ 486	$ 575