Pensions and Other Postretirement Benefit Plans (Schedule of Net Periodic Benefit Plan Cost) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
United States [Member]
Weighted average assumptions used to determine net cost:
Discount rate	4.20%	4.54%	4.18%
Expected return on plan assets	4.40%	4.74%	4.43%
Rate of compensation increase
Non-U.S. Pension Plans [Member]
Weighted average assumptions used to determine net cost:
Discount rate	2.98%	3.67%	3.58%
Expected return on plan assets	4.46%	5.39%	5.52%
Rate of compensation increase	3.29%	3.24%	3.23%
United States Postretirement Benefits Plan [Member]
Weighted average assumptions used to determine net cost:
Discount rate	4.00%	4.24%	3.90%
Expected return on plan assets
Rate of compensation increase
Non-U.S. Postretirement Benefits Plan [Member]
Weighted average assumptions used to determine net cost:
Discount rate	3.70%	4.00%	3.85%
Expected return on plan assets
Rate of compensation increase	3.00%	3.00%	3.00%
Pension Plans [Member]
Components of net periodic benefit cost:
Service cost	$ 2,720	$ 2,656	$ 2,959
Interest cost	7,476	7,885	7,787
Expected return on assets	(8,152)	(8,675)	(8,630)
Amortization of prior service cost/(credit)	36	38	48
Amortization of net actuarial loss	2,628	2,283	2,594
Settlement		162	103
Curtailment (gain)/loss		(111)
Special/contractual termination benefits			44
Net periodic benefit cost	4,708	4,238	4,905
Other postretirement benefits [Member]
Components of net periodic benefit cost:
Service cost	244	254	330
Interest cost	2,214	2,443	2,437
Expected return on assets
Amortization of prior service cost/(credit)	(4,488)	(4,488)	(4,488)
Amortization of net actuarial loss	2,811	2,819	3,338
Settlement
Curtailment (gain)/loss
Special/contractual termination benefits
Net periodic benefit cost	$ 781	$ 1,028	$ 1,617