Employee Pension Plans (Summary Of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Summary of net periodic benefit cost
Interest cost	$ 582	$ 758	$ 1,746	$ 2,273
Service cost	236	231	709	694
Expected return on plan assets	(1,015)	(1,006)	(3,045)	(3,017)
Recognized net actuarial losses	683	592	2,049	1,775
Net periodic benefit cost	$ 486	$ 575	$ 1,459	$ 1,725