Employee Benefit Plans (Components Of Other Comprehensive Loss Related To Defined Benefit Plan And Postretirement Benefit Plan) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Total recognized in accumulated other comprehensive loss	$ (16,536)	$ (19,990)
Deferred tax benefit	4,237	5,122
Amounts included in accumulated other comprehensive loss	(12,299)	(14,868)
Defined Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	(16,412)	(19,894)
Total recognized in accumulated other comprehensive loss	(16,412)	(19,894)
Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	(127)	(133)
Prior service credit (cost)	3	37
Total recognized in accumulated other comprehensive loss	$ (124)	$ (96)