Retirement Benefits (Net Periodic Benefit (Credit) Cost) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 3	$ 4
Interest cost	2,788	3,666
Expected return on plan assets	(3,995)	(4,740)
Amortization of prior service cost		2
Net periodic benefit (credit) cost	(1,204)	(1,068)
Non-U.S. Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	461	404
Interest cost	689	573
Expected return on plan assets	(233)	(210)
Amortization of prior service cost	11	10
Net periodic benefit (credit) cost	928	777
Other Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1
Interest cost	183	211
Expected return on plan assets
Amortization of prior service cost
Net periodic benefit (credit) cost	$ 184	$ 211