Employee and Retiree Benefit Plans (Amount Related to Foreign Benefit Plans) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at December 31	$ 563,825	$ 519,357
Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at December 31	212,533	197,575
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at December 31	881,932	815,593	$ 794,589
Fair value of plan assets at December 31	563,825	519,357	521,682
Net plan liabilities recognized	(318,107)	(296,236)
Net periodic benefit expense (benefit)	24,102	23,358	42,718
Pension Benefits [Member] | Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at December 31	222,483	206,502
Fair value of plan assets at December 31	212,535	197,575
Net plan liabilities recognized	9,948	8,927
Net periodic benefit expense (benefit)	194	(2,244)
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at December 31	106,276	106,679	115,222
Fair value of plan assets at December 31
Net plan liabilities recognized	(106,276)	(106,679)
Net periodic benefit expense (benefit)	4,971	5,575	$ 8,973
Other Postretirement Benefits [Member] | Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at December 31	791	615
Net plan liabilities recognized	791	615
Net periodic benefit expense (benefit)	$ 133	$ 154