Employee Benefit Plans (Schedule of Changes in Projected Benefit Obligations) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation, Beginning Balance	$ 172,143
Defined Benefit Plan, Benefit Obligation, Ending Balance	178,604	$ 172,143
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation, Beginning Balance	172,143	161,955
Defined Benefit Plan, Service Cost	12,502	10,686	$ 10,319
Defined Benefit Plan, Interest Cost	5,405	5,326	4,790
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	0	0
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	0	159	0
Defined Benefit Plan, Actuarial Net (Gains) Losses	(1,045)	11,336
Defined Benefit Plan Settlement Gain Loss	0	(438)
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement	0	12,907
Defined Benefit Plan, Benefits Paid (Deprecated 2017-01-31)	(7,801)	(5,974)
Defined Benefit Plan, Foreign Currency Exchange Rate Changes, Benefit Obligation	(2,600)	2,000
Defined Benefit Plan, Benefit Obligation, Ending Balance	178,604	172,143	161,955
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation, Beginning Balance	70,198	60,524
Defined Benefit Plan, Service Cost	3,028	2,543	2,883
Defined Benefit Plan, Interest Cost	2,319	2,118	2,259
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	432	354
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	0	0	(13,743)
Defined Benefit Plan, Actuarial Net (Gains) Losses	(7,172)	5,510
Defined Benefit Plan Settlement Gain Loss	0	0
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement	0	0
Defined Benefit Plan, Benefits Paid (Deprecated 2017-01-31)	(1,409)	(851)
Defined Benefit Plan, Foreign Currency Exchange Rate Changes, Benefit Obligation	0	0
Defined Benefit Plan, Benefit Obligation, Ending Balance	$ 67,396	$ 70,198	$ 60,524