Employee Benefit Plans (Schedule of Changes in Fair Value of Plan Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	$ 103,236
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	102,561	$ 103,236
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(76,043)	(68,907)
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	103,236	84,770
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	(6,464)	14,481
Defined Benefit Plan, Plan Assets, Contributions by Employer	13,590	22,866
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	0	0
Defined Benefit Plan, Plan Assets, Payment for Settlement	0	(12,907)
Defined Benefit Plan, Benefits Paid (Deprecated 2017-01-31)	(7,801)	(5,974)
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	102,561	103,236
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(76,043)	(68,907)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0	0
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	0	0
Defined Benefit Plan, Plan Assets, Contributions by Employer	977	497
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	432	354
Defined Benefit Plan, Plan Assets, Payment for Settlement	0	0
Defined Benefit Plan, Benefits Paid (Deprecated 2017-01-31)	(1,409)	(851)
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0	0
Defined Benefit Plan, Funded (Unfunded) Status of Plan	$ (67,396)	$ (70,198)