Employee Benefit Plans (Schedule of Change in Projected Benefit Obligation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Benefit Plan [Member]
Change in Projected Benefit Obligation:
Beginning Balance	$ 72,542	$ 75,043
Service Cost	2,308	2,558	$ 1,894
Interest Cost	3,046	2,894	2,682
Actuarial (Gain) Loss	2,810	(5,915)
Benefits Paid	(2,105)	(2,038)
Ending Balance	78,601	72,542	75,043
Other Benefits Plan [Member]
Change in Projected Benefit Obligation:
Beginning Balance	46,249	49,578
Service Cost	1,099	1,373	1,032
Interest Cost	1,952	1,921	1,792
Actuarial (Gain) Loss	141	(6,062)
Benefits Paid	(553)	(561)
Ending Balance	$ 48,888	$ 46,249	$ 49,578