Employee Benefit Plans (Schedule of Change in Projected Benefit Obligation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Benefit Plan [Member]
Change in Projected Benefit Obligation:
Beginning Balance	$ 100,891	$ 83,927
Service Cost	2,434	2,171	$ 2,426
Interest Cost	3,099	3,426	3,061
Actuarial (Gain) Loss	(12,585)	(14,188)
Benefits Paid	(3,148)	(2,821)
Ending Balance	115,861	100,891	83,927
Other Benefits Plan [Member]
Change in Projected Benefit Obligation:
Beginning Balance	55,166	48,474
Service Cost	993	839	1,135
Interest Cost	1,699	1,984	1,898
Actuarial (Gain) Loss	4,279	(4,671)
Benefits Paid	(803)	(802)
Ending Balance	$ 52,776	$ 55,166	$ 48,474