Pensions and Other Postretirement Benefit Plans (Schedule of (Gains)/Losses Recognized in Other Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
(Gains)/losses in plan assets and benefit obligations recognized in other comprehensive income:
Settlements/curtailments		$ (51)	$ (103)
Asset/liability loss/(gain)	(2,955)	5,498	700
Amortization of actuarial (loss)	(5,439)	(5,102)	(5,932)
Amortization of prior service (cost)/credit	4,453	$ 4,450	$ 4,440
Pension Plans [Member]
(Gains)/losses in plan assets and benefit obligations recognized in other comprehensive income:
Settlements/curtailments
Asset/liability loss/(gain)	(4,408)
Amortization of actuarial (loss)	(2,628)
Amortization of prior service (cost)/credit	(36)
Currency impact	1,930
Cost/(benefit) in other comprehensive income	(5,142)
Total cost/(benefit) recognized in net periodic benefit cost and other comprehensive income	(434)
Other postretirement benefits [Member]
(Gains)/losses in plan assets and benefit obligations recognized in other comprehensive income:
Settlements/curtailments
Asset/liability loss/(gain)	2,743
Amortization of actuarial (loss)	(2,811)
Amortization of prior service (cost)/credit	4,488
Currency impact	2
Cost/(benefit) in other comprehensive income	4,422
Total cost/(benefit) recognized in net periodic benefit cost and other comprehensive income	$ 5,203